Continuously and/or infinitely variable transmissions and methods therefor

ABSTRACT

An infinitely variable transmission (IVT) having a rotatable input shaft arranged along a longitudinal axis of the transmission. In one embodiment, the input shaft is adapted to supply a lubricant to the interior of the transmission. In some embodiments, a stator assembly is coupled to, and coaxial with, the input shaft. The IVT has a plurality of planets operably coupled to the stator assembly. The planets are arranged angularly about the longitudinal axis of the transmission. In one embodiment, a traction ring is operably coupled to the planets. The IVT is provided with a housing that is operably coupled to the traction ring. The housing is substantially fixed from rotating with the input shaft. The traction ring is substantially fixed from rotating with the input shaft. In some embodiments, the IVT is provided with a lubricant manifold that is configured to supply a lubricant to the input shaft.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional PatentApplication No. 61/032,834, filed on Feb. 29, 2008, which is herebyincorporated by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The disclosed invention relates generally to mechanical power modulationand transmission. More specifically, the invention concerns continuouslyand infinitely variable units and transmissions, subassemblies,components, and methods for use therewith.

2. Description of the Related Art

In the relevant technology various types of continuously and infinitelyvariable transmissions (C/IVT) are known. For example, one well knownclass of continuous variators is the belt-and-variable-radius-pulleyvariator. Other known variators include hydrostatic, toroidal, andcone-and-ring variators. In some cases, these variators couple to othergearing to provide infinitely variable transmission functionality. Thepresent disclosure is addressed in part to a type of C/IVT typicallyknown as a ball-type rolling traction CVT. To provide a continuously orinfinitely variable transmission, various ball-type rolling tractiontransmissions have been developed in which power is transmitted throughtraction rollers supported in a housing between torque input and outputdiscs. In some such transmissions, traction rollers are mounted onsupport structures configured to cause the engagement of the tractionrollers with the input and output discs in circles of varying diametersdepending on the desired transmission ratio.

Although ball-type rolling traction CVTs have gained some acceptance incertain industrial applications, the technology has generally beenunable to overcome technical and economic hurdles to gain a wideradoption across multiple fields of use. The success of many knownsolutions has been limited. There is a continuing need in the CVT/IVTindustry for transmission and variator improvements in increasingefficiency and packaging flexibility, simplifying operation, andreducing cost, size, and complexity, among other things. The inventiveembodiments disclosed here address many of these challenges. Inparticular, though certainly not limited in scope of applicability,certain inventive embodiments disclosed here provide mechanisms andmethods for employing continuously variable units and/or continuouslyvariable transmissions in vehicle applications.

SUMMARY OF THE INVENTION

The systems and methods herein described have several features, nosingle one of which is solely responsible for its desirable attributes.Without limiting the scope as expressed by the claims that follow, itsmore prominent features will now be discussed briefly. After consideringthis discussion, and particularly after reading the section entitled“Detailed Description of the Preferred Embodiments” one will understandhow the features of the system and methods provide several advantagesover traditional systems and methods.

One aspect of the invention relates to a continuously variabletransmission (CVT) having a number of planets arranged angularly aboutthe longitudinal axis of the CVT, each planet having a through bore thatforms a tiltable axis of rotation of the planet. The CVT furtherincludes a main axle arranged along the longitudinal axis of the CVT anda lubricant manifold coupled to the main axle. The lubricant manifold isadapted to supply lubricant to the main axle. Optionally, the CVT has astator assembly operably coupled to the planets. The stator assembly isconcentric with the longitudinal axis of the transmission.Alternatively, the CVT has a shift rod arranged in a central bore of themain axle. In some cases, the shift rod is adapted to supply thelubricant to the interior of the CVT.

Another aspect of the invention addresses a method for lubricatinginternal components of a transmission. The method includes, in oneembodiment, providing a lubricant manifold configured to cooperate witha lubricant source, providing a main axle adapted to receive thelubricant manifold, providing a shift rod having a central bore andadapted to cooperate with the main axle. The method further includessupplying a lubricant via the lubricant manifold to the main axle anddelivering the lubricant through the main axle to the rod. In someembodiments, the method includes delivering the lubricant through thecentral bore of the shift rod to a shift rod lubricant passage.Optionally, the method includes the step of supplying a pressurizedlubricant via the lubricant source. Alternatively, the method includesthe step of delivering the lubricant through a lubricant deliverypassage of the main axle to the interior of the transmission.

One more aspect of the invention concerns an infinitely variabletransmission that includes an input shaft arranged along thelongitudinal axis of the transmission and operably coupled to a powersource. The transmission further includes a stator assembly coupled tothe input shaft and a number of planets operably coupled to the statorassembly. In some embodiments, the transmission has a means forsupplying lubricant to the input shaft. Optionally, the input shaft andthe stator assembly are rigidly coupled. Alternatively, the means forsupplying a lubricant includes a lubricant manifold adapted to supplylubricant to the input shaft. Optionally, the transmission has a shiftrod operably coupled to the input shaft.

Yet another aspect of the invention involves a mechanism forfacilitating an adjustment in a speed ratio of a transmission. In oneembodiment, the mechanism includes a shift rod having a number oflubricant ports and a closed end. The mechanism can also include a shiftcam body operably coupled to the shift rod, the shift cam body having anumber of lubricant channels. Optionally, the mechanism has a shiftactuation subassembly coupled to the shift rod. Optionally, the shiftactuation subassembly includes a shift pin collar coupled to the shiftrod. The shift pin collar is configured to rotate with an input shaft ofthe transmission. Alternatively, the shift actuation subassemblyincludes a shift screw operably coupled to the shift pin collar. Theshift screw is substantially non-rotatable with an input shaft of thetransmission.

One aspect of the invention is directed to an infinitely variabletransmission that includes an input shaft arranged along thelongitudinal axis of the transmission and a stator assembly coupled to,and coaxial with, the input shaft. The transmission further includes anumber of planets operably coupled to the stator assembly. In oneembodiment, the planets are arranged angularly about the longitudinalaxis of the transmission. The transmission further includes a tractionring operably coupled to the planets and a housing operably coupled tothe traction ring. In one embodiment, the housing is substantially fixedfrom rotating with the input shaft. Optionally, the traction ring issubstantially fixed from rotating with the input shaft. Alternatively,the input shaft and the stator assembly are rigidly coupled. Optionally,the traction ring has a substantially annular ring having a front faceand a rear face and a number of bi-directional ramps located on thefront face. The cross-section of each ramp is curved. Alternatively, thetraction ring has a contact surface located on the rear face.

Another aspect of the invention relates to a mechanism for facilitatingan adjustment of a speed ratio in an infinitely variable transmission.The mechanism includes, in one embodiment, a shift rod arranged along alongitudinal axis of the transmission, a shift nut operably coupled tothe shift rod, and a shift screw operably coupled to the shift nut. Insome embodiments, the shift rod is adapted to supply a lubricant to theinterior of the transmission. Optionally, a rotation of the shift screwaxially translates the shift rod. Alternatively, the shift rod isadapted to supply a lubricant to the interior of the infinitely variabletransmission. Optionally, the mechanism has a shift cam body operablycoupled to the shift rod. The shift cam body has a number of lubricantchannels.

Yet one more aspect of the invention addresses a method of operating aninfinitely variable transmission (IVT). The method includes receivingpower on an input shaft and providing a shift rod arranged along thelongitudinal axis of the IVT. In one embodiment, the shift rod isadapted to supply a lubricant to internal components of the IVT and isalso adapted to facilitate an adjustment speed ratio of the IVT. Themethod further includes transferring power from the input shaft to anumber of planets arranged angularly around the longitudinal axis of theIVT. In one embodiment, the method includes providing an output shaftcoupled to the planets. The output shaft delivers power from the planetsto an external load coupled to the IVT. Optionally, the method includesthe step of coupling a stator assembly to the input shaft. The statorassembly and the input shaft are substantially rotatable. Alternatively,the method includes the step of providing a source of pressurizedlubricant coupled to the IVT. Optionally, the method includes the stepof supplying the pressurized lubricant to the shift rod.

In another aspect, the invention concerns a shift actuation mechanismfor an infinitely variable transmission (IVT). The shift actuationmechanism includes a shift pin collar having a central bore adapted toreceive an input shaft, a shift screw coupled to the shift pin collar,and a control plate coupled to the shift pin collar. The shift actuationmechanism further includes a shift nut coupled to the shift screw. Theshift nut is adapted to be substantially fixed from rotating relative tothe shift screw. In one embodiment, the shift actuation mechanismincludes a shift rod arranged along the longitudinal axis of the IVT andoperably coupled to the shift screw. Optionally, the shift actuator hasa coupling device adapted to cooperate with the shift rod.Alternatively, the shift rod is configured to rotate about thelongitudinal axis of the IVT. Optionally, the shift screw issubstantially fixed from rotation relative to the shift rod.

Another aspect of the invention relates to a shift pin collar for aninfinitely variable transmission (IVT). The shift pin collar is asubstantially cylindrical body with a central bore. A neck is located onthe periphery of the cylindrical body and is adapted to receive abearing. The substantially cylindrical body has a number of holes whichare adapted to receive a coupling device of the IVT.

Yet one more aspect of the invention addresses a shift screw for aninfinitely variable transmission (IVT). The shift screw is asubstantially cylindrical body having a central bore, a threaded portionarranged on the central bore, and a first shoulder arranged on thecentral bore. The first shoulder is adapted to receive a first bearingof the IVT. In one embodiment, the shift screw has a second shoulderlocated on the periphery of the cylindrical body. The second shoulder isadapted to receive a second bearing of the IVT. The shift screw also hasa reaction flange located on the periphery of the cylindrical body.

In another aspect, the invention concerns a lubricant manifold for usewith a transmission. The lubricant manifold is a substantiallydisc-shaped body with a central bore. In one embodiment, the lubricantmanifold has a shoulder located on the central bore that is adapted toreceive a bearing of the transmission. The lubricant manifold has alubricant passage configured to intersect the central bore. Thelubricant passage extends radially from the central bore to an outercircumference of the disc-shaped body. The lubricant manifold also has anumber of grooves arranged on the central that are adapted to receive anumber of seals of the transmission. The lubricant manifold has anengagement shoulder extending from a face of the disc-shaped body and iscoaxial with the central bore. The lubricant manifold also has anengagement face located on a face of the disc-shaped body that isoppositely located to the engagement shoulder. The lubricant manifoldhas a seal groove located on the engagement face. Optionally, thelubricant passage has a threaded portion. Alternatively, the lubricantmanifold has a first and second seal groove. Each seal groove is formedon the central bore. The first seal groove is located on one side of thelubricant passage. The second seal groove is located on a second side ofthe lubricant passage. Alternatively, the threaded portion of thelubricant passage is arranged on the periphery of the disc-shaped body.

One more aspect of the invention concerns a lubricant manifold for usewith a transmission. The lubricant manifold is a circular body with acentral bore. The lubricant manifold has a flange extending from thecircular body. The flange is concentric with the central bore. One sideof the flange is an engagement face. The lubricant manifold also has anengagement hub extending from the engagement face. The engagement hubhas a central pilot recess. The outer face of the engagement hub has areaction surface. The engagement hub also has a lubricant passage bossextending from the flange. Optionally, the central piloting recess has asubstantially square cross-section. Alternatively, the flange has anumber of fastening holes arranged around the periphery of the flange.Optionally, the reaction surface has a substantially circularcross-section.

Yet another aspect of the invention involves a housing cover plate foruse with an infinitely variable transmission (IVT). The housing coverplate is a generally circular body with a central bore. The housingcover plate has a flange coupled to the circular body. The flange isconcentric with the central bore. The housing cover plate has a shoulderlocated on the inner diameter of the circular body and a number oflubricant channels arranged angularly around the circumference of thecircular body. Optionally, the housing cover plate has grooves arrangedon the central bore and adapted to receive a retention device of theIVT. Alternatively, the central bore is adapted to receive a bearing ofthe IVT. Optionally, the flange has a number of fastening holes.

One aspect of the invention concerns a housing cover plate for use witha continuously or infinitely variable transmission (C/IVT). The housingcover plate is a substantially circular disc with a central passage. Thehousing cover plate has a bearing recess formed on the central passageand a thrust washer recess coupled to the central passage in proximityto the bearing recess. The housing cover plate also has a number ofengagement features. The engagement features are arranged on a face ofthe circular body in proximity to the outer circumference. The housingcover plate also has a flange coupled to the periphery of the circularbody. Optionally, the engagement features have a substantially squarecross-section. Alternatively, the flange has a number of fasteningholes. Optionally, the housing cover plate has a groove formed on thecentral passage. The groove is configured to couple to a seal of theC/IVT.

Another aspect of the invention relates to a lubricant sump for use withan infinitely variable transmission (IVT). The lubricant sump is a bodywith a central bore and a number of holes located on an exteriorperimeter edge portion of the body. The holes are adapted for mountingthe body to a support structure of the IVT. The lubricant sump also hasa number of lubricant passages located on the periphery of the body. Thelubricant passages are configured to intersect the central bore. Thelubricant sump has a seal pocket located substantially at the centralbore of the body and a cavity concentric with the central bore. Thecavity is adapted to receive a lubricant of the IVT. Optionally, thebody has a substantially square cross-section.

Yet one more aspect of the invention addresses a mechanism for adjustinga speed ratio range for an infinitely variable transmission (IVT). Themechanism includes a shift rod arranged along the longitudinal axis ofthe IVT. The mechanism, in one embodiment, includes ashift-stop-cylinder assembly. The shift-stop-cylinder assembly isarranged coaxially with the shift rod and is coupled to a first end ofthe shift rod. The mechanism also includes a shift-stop-dowel assembly.The shift-stop-dowel assembly is arranged coaxially with the shift rodand is coupled to a second end of the shift rod. Optionally, theshift-stop-cylinder has a shift stop cylinder coupled to a spring and anadjustment nut. Alternatively, the shift-stop-spring assembly has asubstantially cylindrical dowel coupled to the spring and an adjustmentnut coupled to the spring. Optionally, the adjustment nut is configuredto couple with a main axle of the IVT.

In another aspect, the invention concerns an axial force generating(AFG) mechanism for use in a continuously variable transmission (CVT).The AFG includes a load cam ring. The load cam ring is a substantiallyannular ring having a front face and a rear face. A number ofbi-directional ramps are located on the front face of the load cam ring.The cross-section of the ramps of the load cam ring is curved. The AFGfurther includes a number of load cam rollers coupled to the load camring and a traction ring coupled to the load cam rollers. The tractionring is a substantially annular ring having a front face and a rearface. A number of bi-directional ramps are located on the front face ofthe traction ring. The ramps of the traction ring are adapted to receivethe load cam rollers. The cross-section of the ramps of the tractionring is curved. Optionally, the load cam rollers are substantiallyspherical. Alternatively, the AFG has a preload spring coupled to theload cam ring. Optionally, the preload spring is a wave spring adaptedto couple to the load cam ring.

Another aspect of the invention relates to a load cam ring for use in acontinuously variable transmission (CVT). The load cam ring is asubstantially annular ring having a front face and a rear face. A numberof bi-directional ramps are located on the front face of the load camring. The cross-section of the ramps of the load cam ring is curved.Optionally, the engagement features have a substantially squarecross-section.

In another aspect, the invention concerns a traction ring for use in acontinuously variable transmission. The traction ring is a substantiallyannular ring having a front face and a rear face. A number ofbi-directional ramps are located on the front face of the traction ring.The cross-section of the ramps of the traction ring is curved.Optionally, the engagement features have a substantially squarecross-section. Alternatively, the contact surface has an angle ofinclination in the range of 5 degrees to 75 degrees. Optionally, thecontact surface has an angle of inclination of about 45 degrees.

One more aspect of the invention addresses an output shaft for use witha continuously variable transmission. The output shaft has asubstantially cylindrical neck having a central bore. A reaction flangeextends from one end of the neck and is concentric to the central bore.A number of splines are located on the central bore. A number ofengagement features are located on the peripheral circumference of thereaction flange. Optionally, the output shaft has a number of pilotingguides located on the peripheral circumference of the reaction flange.The piloting guides are substantially aligned with the engagementfeatures about the central bore. Alternatively, the output shaft has abearing support surface arranged on the central bore. Optionally, theoutput shaft has a lubricant passage formed on the cylindrical neck. Thelubricant passage extends radially from the periphery of the cylindricalneck and is configured to intersect the central bore.

Yet another aspect of the invention involves a main axle for use in acontinuously variable transmission (CVT). The main axle is an elongatedbody having a first end portion, a second end portion, and a centralportion. A central bore is formed through the main axis of the elongatedbody, and extends from the first end portion and beyond the middleportion. The central bore has a fluted portion. The main axle has anaxial reaction flange located at the first end portion. A threadedportion is located at the second end portion. The central portion of themain axle includes a first segment extending from the reaction flange, asecond segment extending from the first segment, and a third segmentextending from the second segment. The second segment has a slot. Thethird segment has a lubricant delivery passage and a lubricant inletpassage. The first, second, and third segments define respectiveshoulders that couple to components of the CVT. Optionally, the mainaxle has a first lubricant delivery passage located at the first endportion of the elongated body. Alternatively, the diameter of the firstsegment is larger than the diameter of the second segment. Optionally,the diameter of the second segment is larger than the diameter of thethird segment.

One aspect of the invention concerns an auxiliary axle for use with acontinuously or infinitely variable transmission. The auxiliary axle hasa main body with a central bore. A locking member slot is provided alongthe axial length of the central bore. A reaction flange extends radiallyfrom a central portion of the main body. A lubricant passage is locatedon the reaction flange and intersects the central bore. The auxiliaryaxle has a first shoulder that extends from a first face of the reactionflange. The first shoulder is configured to couple to a stator of thetransmission. Optionally, the auxiliary axle has a second shoulderextending from a second face of the reaction flange. The second shoulderhas a substantially square-cross section. Alternatively, the firstshoulder has a substantially circular cross-section.

Another aspect of the invention relates to a shift rod for use with acontinuously or infinitely variable transmission. The shift rod is anelongated body having a central bore. The central bore is adapted tosupply a lubricant to internal components of the transmission. The shiftrod has a slot located substantially at the central portion of theelongated body. The slot is adapted to supply lubricant to the centralbore. The shift rod has a number of lubricant passages on a first end ofthe elongated body. An actuator engagement passage is located on asecond end of the elongated body. Optionally, one end of the elongatedbody is substantially closed. Alternatively, the shift rod has apiloting stub arranged on one end of the elongated body. Optionally, theshift rod has a seal groove arranged on the periphery of the elongatedbody between the slot and the actuator engagement passage.

Yet one more aspect of the invention addresses an input shaft for use inan infinitely variable transmission (IVT). The input shaft is anelongated body having a first end portion, a second end portion, and acentral portion. A central bore is formed through the main axis of theelongated body, and extends from the first end portion and beyond themiddle portion. The central bore has a fluted portion. The input shafthas an axial reaction flange located at the first end portion. Athreaded portion is located at the second end portion. The centralportion of the input shaft includes a first segment extending from thereaction flange, a second segment extending from the first segment, athird segment extending from the second segment, a fourth segmentextending from the third segment, and a fifth segment extending from thefourth segment. The second segment has a first slot. The third segmenthas a first locking member seat, a lubricant delivery passage, and alubricant inlet passage. The fourth segment has a second slot. The fifthsegment has a second locking member seat. The first, second, third,fourth, and fifth segments define respective shoulders that couple tocomponents of the CVT. Optionally, the second segment has a smallerdiameter than the first segment. Alternatively, the third segment has asmaller diameter than the second segment. Optionally, the fifth segmenthas a smaller diameter than the fourth segment.

In another aspect, the invention concerns a drivetrain casing for usewith a continuously or infinitely variable transmission (C/IVT). Thedrivetrain casing, in one embodiment, has a main body with an exteriorsurface and an interior surface, and also has an upper portion and lowerportion. A mounting portion is arranged on the upper portion of theexterior surface. The mounting portion is configured to couple to ahousing cover of the C/IVT, and has a central passage. A lubricant sumpcavity is located on the lower portion of the main body. Optionally, thedrivetrain casing has a number of fastening bosses arranged on theperiphery of the upper portion. Alternatively, the drivetrain casing hasa mounting surface configured to receive a seal of the C/IVT.Optionally, the drivetrain casing has an interior space partiallyseparated from the lubricant sump cavity.

Another aspect of the invention relates to a continuously variabletransmission (CVT). The CVT includes a number of planets arrangedangularly about the longitudinal axis of the CVT. Each planet has athrough bore that forms a tiltable axis of rotation of the planet. TheCVT includes a load cam ring that is coaxial with the number of planets.The load cam ring is a substantially annular ring having a front faceand a rear face. A number of bi-directional ramps are located on thefront face of the load cam ring. The cross-section of the ramps of theload cam ring is curved. The CVT further includes a number of load camrollers coupled to the load cam ring, and a traction ring coupled to theload cam rollers. The traction ring is a substantially annular ringhaving a front face and a rear face. A number of bi-directional rampsare located on the front face of the traction ring. The ramps of thetraction ring are adapted to receive the load cam rollers. Thecross-section of the ramps of the traction ring is curved. Optionally,the transmission has a main axle arranged along the longitudinal axis ofthe CVT. Alternatively, the transmission has a stator assembly operablycoupled to the planets. The stator assembly is concentric with thelongitudinal axis of the CVT. Optionally, the transmission has alubricant manifold configured to supply a lubricant to the main axle.

Yet another aspect of the invention involves a transmission having anumber of planets arranged about the longitudinal axis of thetransmission. Each planet has a through bore that forms a tiltable axisof rotation of the planet. The transmission has a housing cover. Thehousing cover is a generally circular body with a central bore. Thehousing cover plate has a flange coupled to the circular body. Theflange is concentric with the central bore. The housing cover plate hasa shoulder located on the inner diameter of the circular body and anumber of lubricant channels arranged angularly around the circumferenceof the circular body. Optionally, the transmission has a housingsubassembly coupled to the housing cover. The housing subassemblyincludes a substantially cylindrical body configured to enclosecomponents of the transmission. Alternatively, the housing subassemblyis configured to rotate about the longitudinal axis of the transmission.Optionally, the housing subassembly is substantially fixed from rotatingabout the longitudinal axis of the transmission.

In another aspect of the invention involves a continuously or infinitelyvariable transmission. The transmission includes a number of planetsarranged about the longitudinal axis of the transmission. Each planethas a through bore that forms a tiltable axis of rotation of the planet.The transmission also includes a main axle arranged coaxial with theplanets. The main axle is an elongated body having a first end portion,a second end portion, and a central portion. A central bore is formedthrough the main axis of the elongated body, and extends from the firstend portion and beyond the middle portion. The central bore has a flutedportion. The main axle has an axial reaction flange located at the firstend portion. A threaded portion is located at the second end portion.The central portion of the main axle includes a first segment extendingfrom the reaction flange, a second segment extending from the firstsegment, and a third segment extending from the second segment. Thesecond segment has a slot. The third segment has a lubricant deliverypassage and a lubricant inlet passage. The first, second, and thirdsegments define respective shoulders that couple to components of thetransmission. The transmission also includes an auxiliary axle coupledto the main axle. The auxiliary axle has a main body with a centralbore. A locking member slot is provided along the axial length of thecentral bore. A reaction flange extends radially from a central portionof the main body. A lubricant passage is located on the reaction flangeand intersects the central bore. The auxiliary axle has a first shoulderthat extends from a first face of the reaction flange. The firstshoulder is configured to couple to a stator of the transmission. Thetransmission also includes a stator assembly coupled to, and coaxialwith, the main axle. Optionally, the transmission has a lubricantmanifold coupled to the main axle. The lubricant manifold supplies alubricant to the main axle. Alternatively, the transmission has a shiftrod coupled to the main axle. Optionally, the shift rod is adapted tosupply lubricant to the interior of the transmission.

These and other improvements will become apparent to those skilled inthe relevant technology as they read the following detailed descriptionand view the enclosed figures.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a perspective view of one embodiment of a continuouslyvariable transmission (CVT).

FIG. 2 is a cross-sectional perspective view of the CVT of FIG. 1.

FIG. 3 is a cross-sectional view of the CVT of FIG. 2.

FIG. 4 is a partial cross-sectional perspective view of the CVT of FIG.3.

FIG. 5 is a perspective view of one embodiment of a shift rod that canbe used in the CVT of FIG. 4.

FIG. 6 is a cross-sectional view of the shift rod of FIG. 5.

FIG. 7 is partial cross-sectional view of the CVT of FIG. 1.

FIG. 8 is a perspective view of an embodiment of a main axle that can beused with the CVT of FIG. 7.

FIG. 9 is a cross-sectional view of the main axle of FIG. 8.

FIG. 10 is a perspective view of an auxiliary axle that can be used withthe CVT of FIG. 1.

FIG. 11 is another perspective view of the auxiliary axle of FIG. 10.

FIG. 12 is a cross-sectional view of the auxiliary axle of FIG. 10.

FIG. 13 is a perspective view of a stator assembly that can be used withthe CVT of FIG. 1.

FIG. 14 is yet another cross-sectional view of the CVT of FIG. 1.

FIG. 15 is a perspective view of a first shift cam body that can be usedwith the CVT of FIG. 1.

FIG. 16 is a cross-sectional view of the first shift cam body of FIG.15.

FIG. 16A is a cross-sectional Detail B view of certain features of thefirst shift cam body of FIG. 16.

FIG. 17 is a perspective view of a second shift cam body that cam beused with the CVT of FIG. 1.

FIG. 18 is another perspective view of the second shift cam body of FIG.17.

FIG. 19 is a table of coordinates for a shift cam surface profile thatcan be used for the shift cam bodies of FIGS. 15 and 17.

FIG. 20 is a cross-sectional, Detail A view of the CVT of FIG. 1 showinga planet-and-shift-lever subassembly.

FIG. 21 is a perspective view of a planet-and-shift-lever subassemblythat can be used with the CVT of FIG. 1.

FIG. 22 is a cross-sectional view of the planet-and-shift-leversubassembly of FIG. 21.

FIG. 23 is an exploded perspective view of the planet-and-shift-leversubassembly of FIG. 21.

FIG. 24 is yet another partial cross-sectional perspective view ofcertain components of the CVT of FIG. 1.

FIG. 25 is a perspective view of one embodiment of a load cam ring thatcan be used with the CVT of FIG. 1.

FIG. 26 is another perspective view of the load cam ring of FIG. 25.

FIG. 27 is a cross-sectional view of the load cam ring of FIG. 25.

FIG. 28 is a perspective view of one embodiment of a traction ring thatcan be used with the CVT of FIG. 1.

FIG. 29 is a cross-sectional view of the traction ring of FIG. 28.

FIG. 30 is a perspective view of one embodiment of an output shaft thatcan be used with the CVT of FIG. 1.

FIG. 31 is another perspective view of the output shaft of FIG. 30.

FIG. 32 is a cross-sectional view of the output shaft of FIG. 30.

FIG. 33 is yet another partial cross-sectional view of the CVT of FIG.1.

FIG. 34 is a perspective view of an embodiment of a first housing coverplate that can be used with the CVT of FIG. 1.

FIG. 35 is another perspective view of the first housing cover plate ofFIG. 34.

FIG. 36 is a cross-sectional view of the first housing cover plate ofFIG. 34.

FIG. 37 is a perspective view of an embodiment of a second housing coverplate that can be used with the CVT of FIG. 1.

FIG. 38 is a cross-sectional view of the second housing cover plate ofFIG. 37.

FIG. 39 is a perspective view of an embodiment of a lubricant manifoldthat can be used with the CVT of FIG. 1.

FIG. 40 is another perspective view of the lubricant manifold of FIG.39.

FIG. 41 is a cross-sectional view of the lubricant manifold of FIG. 39.

FIG. 42 is yet another cross-sectional view of the CVT of FIG. 1.

FIG. 43 is a perspective view of an embodiment of a drivetrain casingthat can be used with the CVT of FIG. 1.

FIG. 44 is a plan view of the drivetrain casing of FIG. 43.

FIG. 45 is another plan view of the drivetrain casing of FIG. 43.

FIG. 46 is a perspective view of one embodiment of an infinitelyvariable transmission (IVT).

FIG. 47 is a cross-sectional perspective view of the IVT of FIG. 46.

FIG. 48 is a cross-sectional view of the IVT of FIG. 46.

FIG. 49 is another cross-sectional view of the IVT of FIG. 46.

FIG. 50 is a plan view of an embodiment of an input shaft that can beused with the IVT of FIG. 46.

FIG. 51 is a cross-sectional view of the input shaft of FIG. 50.

FIG. 52 is a perspective view of an embodiment of a shift rod that canbe used with the IVT of FIG. 46.

FIG. 53 is a cross-sectional view of the shift rod of FIG. 53.

FIG. 54 is another cross-sectional view of the IVT of FIG. 46.

FIG. 55 is a perspective view of one embodiment of a shift pin collarthat can be used with the IVT of FIG. 46.

FIG. 56 is a cross-sectional view of the shift pin collar of FIG. 55.

FIG. 57 is a perspective view of an embodiment of a shift nut that canbe used with the IVT of FIG. 46.

FIG. 58 is a perspective view of one embodiment of a shift screw thatcan be used with the IVT of FIG. 46.

FIG. 59 is a cross-sectional view of the shift screw of FIG. 58.

FIG. 60 is a perspective view of one embodiment of a control plate thatcan be used with the IVT of FIG. 46.

FIG. 61 is a perspective view of an embodiment of a lubricant manifoldthat can be used with the IVT of FIG. 46.

FIG. 62 is another perspective view of the lubricant manifold of FIG.46.

FIG. 63 is a cross-sectional view of the lubricant manifold of FIG. 46.

FIG. 64 is yet another cross-sectional view of the IVT of FIG. 46.

FIG. 65 is a perspective view of an embodiment of a first housing coverplate that can be used with the IVT of FIG. 46.

FIG. 66 is a cross-sectional view of the first housing cover plate ofFIG. 46.

FIG. 67 is a perspective view of one embodiment of a lubricant sump thatcan be used with the IVT of FIG. 46.

FIG. 68 is another perspective view of the lubricant sump of FIG. 67.

FIG. 69 is a cross-sectional perspective view of the lubricant sump ofFIG. 67.

FIG. 70 is a perspective view of one embodiment of a tractor rear endassembly configured to cooperate with the IVT of FIG. 46.

FIG. 71 is a partial cross-sectional view of another embodiment of aninfinitely variable transmission (IVT).

FIG. 72 is a cross-sectional detail view of an embodiment of ashift-stop-spring assembly that can be used with the IVT of FIG. 71.

FIG. 73 is an exploded, partial cross-sectional perspective view of theshift-stop-spring assembly of FIG. 72.

DETAILED DESCRIPTION OF THE FIGURES

The inventive embodiments disclosed here relate to technology describedin U.S. patent application Ser. Nos. 11/243,484, 11/585,677, and60/948,152, which are hereby incorporated herein by reference inentireties. As used here, the terms “operationally connected,”“operationally coupled”, “operationally linked”, “operably connected”,“operably coupled”, “operably linked,” and like terms, refer to arelationship (mechanical, linkage, coupling, etc.) between elementswhereby operation of one element results in a corresponding, following,or simultaneous operation or actuation of a second element. It is notedthat in using said terms to describe inventive embodiments, specificstructures or mechanisms that link or couple the elements are typicallydescribed. However, unless otherwise specifically stated, when one ofsaid terms is used, the term indicates that the actual linkage orcoupling may take a variety of forms, which in certain instances will beobvious to a person of ordinary skill in the relevant technology.

Components which are used on both the right and left side of atransmission or equipment are designated with the letters a and b. Forexample, where there are two axial force generator subassemblies 2800,the first axial force generator subassembly 2800A, while the secondaxial force generator subassembly 2800B. Generally, all of thecomponents on a side are designated with the letter a, and allsubstantially similar components on another side are designated with theletter b; when a component is referred to generically without a sidedesignation, the a or b suffix is removed.

Referring to FIGS. 1-4 now, a continuously variable transmission (CVT)100 is shown. The CVT 100 is particularly suitable for, among otherapplications, vehicles such as a utility kart, a recreational go-kart, aracing go-kart or the like. In use, the CVT 100 couples between a primemover (for example, a gas powered engine, motor or the like) and a load(for example a rear axle assembly) for varying torque applied from theprime mover to the load. As discussed below in greater detail,components of the CVT 100 are arranged and interconnected in a mannerthat facilitates torque and speed being adjusted in a continuouslyvariable manner.

Still referring to FIGS. 1-4, in one embodiment, a main axle 1000supports a shift-cam-and-sun subassembly 1300 in a manner allowingtranslation of the shift-cam-and-sun subassembly 1300 along alongitudinal axis L1 of the main axle 1000. The main axle 1000 supportsan auxiliary axle 1600 in a manner that coincidentally aligns alongitudinal axis L2 of the auxiliary axle 1600 with the main axlelongitudinal axis L1 and that inhibits unrestricted relative rotation ofthe auxiliary axle 1600 with respect to the main axle 1000. The mainaxle 1000 and the auxiliary axle 1600 jointly support a statorsubassembly 1700 such that a centerline axis C1 of the statorsubassembly 1700 extends coincidentally with the main axle longitudinalaxis L1. A number of planet-and-shift-lever subassemblies 2100 isarrayed angularly around the main axle longitudinal axis L1 and issupported jointly by the shift-cam-and-sun subassembly 1300 and thestator subassembly 1700.

The main axle 1000 supports an output shaft 2300 in a manner such that alongitudinal axis L3 of the output shaft 2300 extends coincidentallywith the main axle longitudinal axis L1. The output shaft 2300 and themain axle 1000 are engaged in a manner allowing the output shaft 2300 torotate with respect to the main axle 1000 about the output shaftlongitudinal axis L3. The output shaft 2300 and the auxiliary axle 1600jointly support a housing subassembly 2600 in a manner thatcoincidentally aligns a centerline axis C2 of the housing subassembly2600 with the main axle longitudinal axis L1 and that allows relativerotation of the housing subassembly 2600 with respect to the outputshaft 2300 and the auxiliary axle 1600. The main axle 1000 and theauxiliary axle 1600 jointly support a lubricant manifold 2700 in amanner inhibiting unrestricted relative rotation of the lubricantmanifold 2700 with respect to the main axle 1000. A shift rod 3000extends though the main axle 1000 and couples to the shift-cam-and-sunsubassembly 1300 for facilitating selective translation of theshift-cam-and-sun subassembly 1300 along the main axle longitudinal axisL1.

Each one of the planet-and-shift-lever subassemblies 2100 is supportedin a manner that allows synchronous rotation of all theplanet-and-shift-lever subassemblies 2100 about a respective referenceaxis T 1 extending through a planet 2102 of each one of theplanet-and-shift-lever subassemblies 2100. Through such synchronousrotation, all of the planet-and-shift-lever subassemblies 2100 aresubstantially in the same relative rotational position at a given pointin time. An axis T1 (see FIGS. 1-3) associated with each one of theplanet-and-shift-lever subassemblies 2100 extends through a center pointof the respective planet 2102 substantially perpendicular to a referenceaxis RI extending radially from the main axle longitudinal axis L1.

Referring now to FIGS. 3 and 4, in one embodiment, a first axial forcegenerator subassembly 2800A couples between the housing subassembly 2600and the planets 2102 of the planet-and-shift-lever subassemblies 2100and a second axial force generator subassembly 2800B couples between theoutput shaft 2300 and each one of the planets 2102. In one embodiment,the axial force generator subassemblies 2800A, 2800B are elements of anaxial force generator that maintains forced engagement between the axialforce generator subassemblies 2800A, 2800B and the planets 2102. In oneembodiment, the first axial force generator subassembly 2800A couples tothe housing subassembly 2600 in a manner inhibiting unrestrictedrelative rotation of the first axial force generator subassembly 2800Awith respect to the housing subassembly 2600. The second axial forcegenerator subassembly 2800B couples to the output shaft 2300 in a mannerinhibiting unrestricted relative rotation of the second axial forcegenerator subassembly 2800B with respect to the output shaft 2300. Thefirst axial force generator subassembly 2800A, the second axial forcegenerator subassembly 2800B, and the shift-cam-and-sun subassembly 1300jointly locate each one of the planets 2102 in a manner thatsubstantially inhibits the axial translation of the planets 2102 andsubstantially constrains the angular translation of the planets 2102about the respective reference axis T1.

During operation of the CVT 100, the main axle 1000 and the lubricantmanifold 2700 are held stationary through rigid connection of thelubricant manifold 2700 to a mating structure (for example, a drivetraincasing 3700 shown in FIG. 43) and a non-rotating interconnection of thelubricant manifold 2700 with the main axle 1000. The housing subassembly2600 can be configured to exert torque on the first axial forcegenerator subassembly 2800A such as through a power input device 2900attached to the housing subassembly 2600. Examples of the power inputdevice 2900 include, but are not limited to, a sprocket (shown in FIGS.3 and 4), a pulley, a cog, a hub, etc. Through traction at a respectivefirst traction interface TI1 between the input axial force generatorsubassembly 2800A and each planet 2102, torque is exerted by the firstaxial force generator subassembly 2800A on the planets 2102, therebycausing each planet 2102 to rotate about a respective planetlongitudinal axis L4. The first traction interface TI1 is defined, asused here, as a region of contact between the first axial forcegenerator subassembly 2800A and the respective planet 2102.

Through traction at a respective second traction interface TI2 betweenthe second axial force generator subassembly 2800B and each planet 2102,torque is exerted by the planets 2102 on the second axial forcegenerator subassembly 2800B, thereby causing the second axial forcegenerator subassembly 2800B and output shaft 2300 to jointly rotateabout the main axle 1000. The second traction interface TI2 is defined,as used here, as a region of contact between the second axial forcegenerator subassembly 2800B and the respective planet 2102.

Turning now to a brief discussion of power flow through the CVT 100 andstill referring to FIGS. 3 and 4, the torque input device 2900 hastorque exerted thereon from a power source (for example an engine) andexerts torque to the housing subassembly 2600. The exertion of torque onthe housing subassembly 2600 urges the housing subassembly 2600 torotate about the main axle longitudinal axis L1. The housing subassembly2600 exerts torque to the first axial force generator subassembly 2800A,which is then transferred from the first axial force generatorsubassembly 2800A to each planet 2102 via the respective first tractioninterface TI1. In response to the exertion of torque on the planets2102, the planets 2102 each rotate about their respective planetlongitudinal axis L4 thereby transferring torque to the second axialforce generator subassembly 2800B via the respective second tractioninterface TI2. The second axial force generator subassembly 2800B exertstorque on the output shaft 2300 thereby urging the output shaft 2300 torotate about the output shaft longitudinal axis L3. It will be readyapparent to a person of ordinary skill in the relevant technology thatthe power flow through the CVT 100 can be reversed by providing a powerinput at the shaft 2300 and, by following the reverse of the power pathdescribed above, taking power out at the torque transmitting device2900.

Synchronous rotation of all the planet-and-shift-lever subassemblies2100 about the respective reference axis T1 allow a torque ratio of theCVT 100 to be varied. The torque ratio refers to a relative position ofthe first traction interface TI1 and the second traction interface TI2for a given angular orientation (that is, tilt) of theplanet-and-shift-lever subassemblies 2100. When the surface speed of theplanets 2102 at the respective first traction interface TI1 is the sameas the surface speed of the planets 2102 at the respective secondtraction interface TI2, the torque ratio is substantially 1:1 and,ignoring system inefficiencies, there is no corresponding torquemultiplication. Through controlled tilting of the planet-and-shift-leversubassemblies 2100, the ratio of the surface speed at the first tractioninterfaces TI1 to that of the surface speed at the second tractioninterfaces TI2 is selectively adjustable, thereby adjusting torqueratio. As discussed further below, the shift-cam-and-sun subassembly canbe configured such that translation of the shift-cam-and-sun subassembly1300 causes such tilt of the planet-and-shift-lever subassemblies 2100.The direction of tilt of the planet-and-shift-lever subassemblies 2100from the position corresponding to the torque ratio of 1:1 dictateswhether the corresponding torque multiplication is greater than 1 (thatis, torque output is greater than torque input) or less than 1 (that is,torque input is greater than torque output).

As depicted in FIGS. 3 and 4, the first traction interface TI1 and thesecond traction interface TI2 are angularly equidistant relative to therespective reference axis RI extending through the correspondingtangential reference axis T1 (See FIG. 4). Ignoring inefficiency andcreep effects, the torque ratio is 1:1 when the longitudinal axis L4 ofeach planet 2102 is parallel with the longitudinal axis L1 of the mainaxle 1000; in which case, the surface speed of the planets 2102 at thefirst traction interface TI1 is substantially the same as the surfacespeed of the planets 2102 at the second traction interface TI2. Such anequidistant configuration provides for a balanced adjustment range suchthat, in some embodiments, full adjustment of the planet-and-shift-leversubassemblies 2100 in a first adjustment direction (for example,yielding torque multiplication) results in substantially the inversevalue as full adjustment in a second direction (for example, yieldingtorque division). In other embodiments, the first traction interface TI1and the second traction interface TI2 can be non-equidistant from thereference axis T1 when the torque ratio is 1:1 and the main axlelongitudinal axis L1 is parallel with the planet longitudinal axis L4.Such a non-equidistant configuration provides for biasing of theadjustment range such that full adjustment of the planet-and-shift-leversubassemblies 2100 in the first adjustment direction results inasymmetric torque multiplication or division values than full adjustmentin the second adjustment direction.

Presented now is a brief description of torque ratio variationfunctionality provided by a Continuously Variable Transmission (CVT) inthe context of the disclosures made herein (for example, the CVT 100).Such CVT functionality allows essentially every fractional torque ratiowithin a given range to be selected in a continuous manner as opposed toa discrete or stepped manner. For example, in the case of the CVT 100disclosed herein, the ability to adjust torque ratio in a continuousmanner over a defined torque ratio range is through angular control ofthe planet-and-shift-lever subassemblies 2100.

It should be noted that such CVT functionality does not inherently offerrotational direction change through torque ratio adjustment. For a givenCVT construction, power input rotational direction with respect to poweroutput rotational direction is fixed (that is, the same direction or theopposite direction). For example, referring to the CVT 100 and FIG. 3,power input rotational direction with respect to power output rotationaldirection is fixed in the same direction—counter-clockwise rotation ofthe power input device 2900 causes counter-clockwise rotation of theoutput shaft 2300 and clockwise rotation of the power input device 2900causes clockwise rotation of the output shaft 2300. For a constantrotational speed of the power input device 2900, varying angularpositioning of the planet-and-shift-lever subassemblies 2100 serves onlyto increase or decrease the rotational speed of the planets 2102,thereby causing a proportional and respective increase or decrease inrotation speed of the output shaft 2300 under the assumption that thereis negligible or limited slippage between the planets 2102 and thesecond axial force generator subassembly 2800B. For the CVT 100, thefirst axial force generator subassembly 2800A, the planets 2102 and thesecond axial force generator subassembly 2800B always rotate in the samedirection.

Returning now to discussing construction and elements of the CVT 100, asbest shown in FIGS. 5 and 6, one embodiment of the shift rod 3000includes an elongated tubular body 3005 having a slot 3010, lubricantpassages 3015, a coupling device passage 3020, an actuator engagementpassage 3025, and a central bore 3026. The central bore 3026 can extendalong the entire length of the tubular body 3005 or, alternatively, aportion of the length. The slot 3010, the lubricant passages 3015, thecoupling device passage 3020 and the actuator engagement passage 3025extend between an exterior surface of the elongated tubular body 3005 tothe central bore 3026.

Referring to FIGS. 3-6, the shift rod 3000 can be slidably engagedwithin a main axle longitudinal passage 1001 for affecting synchronousrotation of the planet-and-shift-lever subassemblies 2100. A couplingdevice 1002 such as a roll pin couples the shift rod 3000 to theshift-cam-and-sun subassembly 1300. The coupling device 1002 extendsthrough the coupling device passage 3020 and is fixedly engaged withinmating holes of the shift-cam-and-sun subassembly 1300 such that axialtranslation of the shift rod 3000 causes a corresponding axialtranslation of the shift-cam-and-sun subassembly 1300. Throughengagement of the shift-cam-and-sun subassembly 1300 with all of theplanet-and-shift-lever subassemblies 2100, translation of theshift-cam-and-sun subassembly 1300 causes all of theplanet-and-shift-lever subassemblies 2100 to synchronously rotate theabout the respective axis T1 thereby resulting in an adjustment of thetorque ratio. The slot 3010 allows lubricant to flow from the lubricantmanifold 2700 into the shift rod central bore 3026 with the shift rod3000 at various translated positions. The lubricant passages 3015 allowlubricant to flow from the central bore 3026 to the shift-cam-and-sunsubassembly 1300.

Referring now to FIGS. 7-9, in one embodiment, the main axle 1000 can beconfigured for having the shift-cam-and-sun subassembly 1300, theauxiliary axle 1600, the stator subassembly 1700, the housingsubassembly 2600, and the lubricant manifold 2700, axially constrainedbetween an axial reaction flange 1003 and a main axle nut 1004 (FIG. 7).In one embodiment, the main axle 1000 includes a first end portion 1006,a second end portion 1008, and a central portion 1010. The axialreaction flange 1003 is located at the first end portion 1006, andthreads 1012 are provided at the second end portion 1008. The main axlenut 1004 includes a threaded bore configured for mating with the threads1012. The axial reaction flange 1003 can be fixedly attached to the mainaxle 1000 adjacent the first end portion 1006.

In one embodiment, the main axle 1000 includes various structuralfeatures configured for engaging mating components of subassembliesand/or related fastening devices. The central portion 1010 can include afirst segment 1014 of a first diameter, a second segment 1016 of asecond diameter, a third segment 1018 of a third diameter, a slot 1020,a locking member seat 1022 (for example, a recess configured forreceiving a key), a first lubricant delivery passage 1024, a secondlubricant delivery passage 1025, and a lubricant inlet passage 1026. Thefirst segment 1014 can extend from an inboard face 1027 of the axialreaction flange 1003, with the second segment 1016 extending from thefirst segment 1014, and the third segment 1018 extending from the secondsegment 1016. In this manner, the segments 1014, 1016, and 1018 candefine respective shoulders on which various components and/orsubassemblies can be mounted. The second end portion 1006 of the mainaxle 1000 can include a shoulder 1028 extending from an outboard face1030 of the axial reaction flange 1003, which shoulder 1028 can have arecess 1032 therein to provide axial clearance for a shaft (not shown)engaged within a splined bore 2310 of the output shaft 2300.

In one embodiment, the main axle longitudinal passage 1001 extends alongthe longitudinal axis L1 between the first end portion 1006 and thesecond end portion 1008 of the main axle 1000. The slot 1020, thelubricant delivery passages (1024, 1025), and the lubricant inletpassage 1026 each extend communicatively between a respective exteriorface of the main axle 1000 and the longitudinal passage 1001. Adjacentto the first end portion 1006 of the main axle 1000, the longitudinalpassage 1001 can be configured to receive a bushing 1036A and a bushing1036B (See FIG. 7). The bushings 1036A and 1036B slidably support andalign the shift rod 3000. In some embodiments, the placement of thebushings 1036A and 1036B form a groove that can be adapted to receive,for example, an o-ring. In one embodiment, at least a portion of thelongitudinal passage 1001 includes flutes 1049 (See FIGS. 7 and 9),which serve to reduce the amount of surface contact between the mainaxle 1000 and the shift rod 3000 for reducing force required totranslate the shift rod 3000, and for allowing the flow of the lubricantbetween the shift rod 3000 and the main axle longitudinal passage 1001.

As best shown in FIGS. 10-12, in one embodiment, the auxiliary axle 1600includes a reaction flange 1605, a first shoulder 1608, a secondshoulder 1615, a central bore 1625, a locking member slot 1628, andlubricant passages 1630. The first shoulder 1608 extends from a firstside face 1632 of the reaction flange 1605. The second shoulder 1615extending from a second side face 1634 of the reaction flange 1605. Thecentral bore 1625 and the locking member slot 1628 each extend betweenopposing ends of the auxiliary axle 1600. The lubricant passages 1630extend between the central bore 1625 and an exterior surface of thereaction flange 1605. The first shoulder 1608 can have a circularcross-sectional shape and the second shoulder 1615 can have arectangular cross-sectional shape. However, it is disclosed herein thatthe shoulders 1608, 1615 are not limited to any particularcross-sectional shape.

Referring to FIGS. 7 and 10-12, the auxiliary axle 1600 can be mountedon the third segment 1018. In one embodiment, a locking member 1034 (SeeFIG. 7) engages between the locking member channel 1628 of the auxiliaryaxle 1600 and the locking member seat 1022 of the main axle 1000.Engagement of the locking member 1034 between the locking member channel1628 and the locking member seat 1022 inhibits unrestricted rotation ofthe auxiliary axle 1600 with respect to the main axle 1000. Thelubricant passages 1630 allow the flow of lubricant from the shift rodcentral bore 3026 to subsystem components adjacent to the reactionflange 1605.

As shown in FIG. 13 as an illustrative example, in one embodiment, thestator subassembly 1700 includes a first stator 1705A, a second stator1705B, and stator connecting rods 1710. The stators 1705A, 1705B arepreferably, but not necessarily, essentially identical in constructionand can sometimes be referred to herein generically as the stator 1705.The stators 1705A, 1705B are arranged in an opposing face-to-facefashion. The stator connecting rods 1710 fixedly couple between thestators 1705A, 1705B by means such as threaded fasteners, for example.The stators 1705A, 1705B can include dowel pin holes (not shown) forreceiving dowels pins to limit relative motion between the stators1705A, 1705B. Alternatively, the stator connecting rods 1710 can serveas dowels, being received in respective dowel holes of the stators1705A, 1705B. Alternatively, the stator connecting rods 1710 are notused; in such embodiments, it is preferable to ensure a constant, orcontrollable, relative angular position of the stator 1705A versus theangular position of the stator 1705B. In some embodiments, the statorassembly 1700 includes two stators formed as a single piece. The statorassembly 1700 can take many different forms to provide substantiallysimilar functionality as described in this disclosure.

The stator 1705 can include a number of shift lever guide flanges 1715.In one embodiment, the shift lever guide flanges 1715 extend from a mainbody 1720 and are oriented in a radially extending manner. A planet axlepassage 1725 extends between each adjacent pair of shift lever guideflanges 1715. Preferably, but not necessarily, the shift lever guideflanges 1715 are uniformly spaced around a central bore 1730 of thestator 1705 whereby the stator 1705 is generally circularly shaped andsymmetrical with respect to the central bore 1730. Each shift leverguide flange 1715 includes a skew roller reaction surface 1735 and ashift guide roller reaction surface 1740. The skew roller reactionsurface 1735 is substantially flat and the shift guide roller reactionsurface 1740 is contoured. Examples of such contour include, but are notlimited to, semi-circular, parabolic, elliptical and angularly tapered.Adjacent skew roller reaction surfaces 1735 of adjacent shift leverguide flanges 1715 extend substantially parallel to each other andadjacent shift guide roller reaction surfaces 1740 of adjacent shiftlever guide flanges 1715 are substantially aligned.

Referring to FIGS. 7, 9, 10, and 13, in one embodiment, the statorsubassembly 1700 mounts jointly on the first segment 1014 of the mainaxle 1000 and a first shoulder 1608 of the auxiliary axle 1600. The bore1730 of the first stator 1705A engages the first segment 1014 of themain axle 1000 and the bore 1730 of the second stator 1705B engages thefirst shoulder 1608 of the auxiliary axle 1600. In this manner, thestator subassembly 1700 is axially constrained between the axialreaction flange 1003 of the main axle 1000 and the reaction flange 1605of the auxiliary axle 1600. Furthermore, the stator subassembly 1700 canbe engaged with the main axle 1000 in a manner that inhibitsunrestricted relative rotational movement between the stator subassembly1700 and the main axle 1000. It is disclosed herein that the statorsubassembly 1700 can be engaged with the main axle 1000 and/or theauxiliary axle 1600 by any suitable fastening method or methods.Examples of such suitable fastening methods include, but are not limitedto, interference press fit, threaded fastener and mating threaded holes,keyed engagement, splined engagement, etc. For example, one or both ofthe stators 1705A, 1705B can be secured using screws or bolts (notshown) that engage mating threaded holes (not shown) of the main axle1000 and/or the auxiliary axle 1600.

As best shown in FIG. 14, in one embodiment, the shift-cam-and-sunsubassembly 1300 includes a first shift cam body 1302, a second shiftcam body 1304, a sun 1306, and bearings 1308. The sun 1306 can beoperationally coupled to the first shift cam body 1302 through thebearings 1308, thereby allowing the sun 1306 to rotate with respect tothe first shift cam body 1302. The bearings 1308 can be configured totransfer axial and radial loads between the sun 1306 and the first shiftcam body 1302. The sun 1306 and the first shift cam body 1302 can beconfigured to receive the bearings 1308.

As best shown in FIGS. 15 and 16, in one embodiment, the first shift cambody 1302 includes an extension 1310, a shift cam 1312, a central bore1314, coupling member holes 1316, lubricant channels 1318, a bearingshoulder 1320, and a retention device groove 1324. The extension 1310can have a generally cylindrical shape and the shift cam 1312 can have agenerally round shape. The shift cam 1312 can be integrally formed witha first end portion 1326 of the extension 1310. An angled edge 1327 ofthe shift cam 1312 can be provided for directing lubrication from theshift cam 1312 to adjacent components of the CVT 100, as well asproviding clearance for planets 2102. The retention device groove 1324can be formed in a second end portion 1328 of the extension 1310. Thesecond end portion 1328 can include a reduced diameter segment 1329 thatdefines the bearing shoulder 1320. The central bore 1314 extends throughthe extension 1310 between the end portions 1326, 1328. The couplingmember holes 1316 and the lubricant channels 1318 extend through theextension 1310 at respective positions between the first and second endportions 1326, 1328. The shift cam 1312 has a shift cam surface 1330defining a respective shift cam surface profile.

Referring to FIGS. 15-18 now, in one embodiment, the second shift cambody 1304 includes a shift cam 1332 and a central bore 1334 (See FIGS.17 and 18). The shift cam 1332 has a shift cam surface 1335 defining arespective geometric shift cam surface profile. The central bore 1334 isconfigured for allowing the second shift cam body 1304 to be mounted atthe reduced diameter segment 1329 of the first shift cam body 1302 witha reaction surface 1336 abutting the bearing shoulder 1320 of the firstshift cam body 1302. A retention device (not shown) such as a snap ringengages the retention device groove 1324 for fixedly securing the secondshift cam body 1304 to the first shift cam body 1302. In otherembodiments, the first shift cam body 1302 is coupled to the secondshift cam body 1304 via, for example, threads, welds, swage, and thelike.

In some embodiments, the shift cam surfaces 1330, 1335 of the shift cambodies 1302, 1304 have substantially identical shift cam surfaceprofiles. One embodiment of data points defining a shape of the shiftcam profiles 1330, 1335 is shown in the table of FIG. 19. TheX-dimension refers to an axial reference distance to a point on theshift cam surface and the corresponding Y-dimension refers to a radialreference distance to the point on the shift cam surface. A shift camsurface profile defines, in part, the sensitivity of the change in thespeed ratio of the CVT 100 for a given control input, such as the axialmovement of the shift-cam-and-sun subassembly 1300. The shift camsurface profile, in one embodiment, defines an angular position Gamma ofthe planet-and-shift-lever subassemblies 2100 as a function of the axialposition X of the shift-cam-and-sun subassembly 1300. In someembodiments, the shift cam surface profile is configured to yield alinear relationship between Gamma and X; in other embodiments, the shiftcam surface profile is configured to yield a non-linear relationshipbetween Gamma and X. In yet other embodiments, the shift cam surfaceprofile is configured such that an X translation of theshift-cam-and-sun subassembly 1300 when the CVT 100 is near the 1:1speed ratio results in substantially more, or alternative less, changein Gamma than a similar X translation when the CVT 100 is near a extremeratio limit. Additionally, in some embodiments the shift cams surfaces1330 and 1335 of shift cam bodies 1302 and 1304 can have substantiallydifferent shift cam surface profiles, if for example it was desired tohave a different shift rate when relative to the axial displacement ofthe shift-cam-and-sun subassembly 1300 when shifting from overdrive tounderdrive compared to shifting from underdrive to overdrive.

As shown in FIG. 14, in one embodiment, the sun 1306 can have agenerally cylindrical shape with internal recesses 1340 for receivingthe bearings 1308 and a central shoulder 1342 that facilitates axialconstraint of the bearings 1308 for limiting an insertion depth of eachone of the bearings 1308 within the respective one of the recesses 1340.The inventive embodiments are not limited to particular ways forpositioning the bearings 1308 with respect to the sun 1306. For example,in other embodiments, a bearing 1308 has an outer race with an integralpositioning flange that engages an exterior edge face of the sun 1306.In still other embodiments, the recesses 1340 have a tapered face andeach one of the bearings 1308 has an outer race with a tapered exteriorsurface that engages the tapered face of the respective one of therecesses 1340. In still other embodiments, the central shoulder 1342 canbe omitted and a discrete spacer can be used to facilitate properspacing between the bearings 1308.

Still referring to FIG. 14, the first shift cam body 1302 is slidablymounted on the second segment 1016 of the main shaft 1000. Relativeposition of the first shift cam body 1302 and placement of the couplingmember holes 1316 is such that the coupling member holes 1316 remainaligned with the main axle slot 1020 over a desired longitudinal travelof the shift-cam-and-sun subassembly 1300 for facilitating coupling ofthe shift-cam-and-sun subassembly 1300 to the shift rod 3000.Furthermore, relative position of the first shift cam body 1302 andplacement of the lubricant channels 1318 is such that one or more of thelubricant channels 1318 remains aligned with the main axle slot 1020over the desired longitudinal travel of the shift-cam-and-sunsubassembly 1300 for maintaining an open lubricant flow path between theshift rod central bore 3026 and the one or more of lubricant channels1318. In this manner, a flow path is provided between the shift rodcentral bore 3026 and the lubricant channels 1318.

Referring now to FIGS. 20-23, in one embodiment, each one of theplanet-and-shift-lever subassemblies 2100 includes a planet 2102rotatably mounted on a planet axle 2104, which can be positioned on aplanet central bore 2103. In some embodiments, each planet 2102 can bespherical in shape. Spaced apart planet bearings 2108 and an innerspacer 2110 can mount coaxially on the planet axle 2104. In someembodiments, the inner spacer 2110 is positioned between the planetbearings 2108. Accordingly, each planet 2102 is rotatably mounted on arespective planet axle 2104 in a rotatable manner. It is disclosedherein that the inventive embodiments are not limited to particularplanet bearing and spacer arrangements for rotatably mounting eachplanet 2102 on the respective planet axle 2104. For example, in someembodiments, a planet bearing and spacer arrangement using more than twoor less than two planet bearings and the addition of one or more outerspacers can be implemented.

Planet axle shift levers 2106 (“shift levers 2106”) can be fixedlyattached to opposing end portions 2107 of the planet axle 2104 such thatthe planet 2102 is positioned between the shift levers 2106. The planetaxle 2104 extends through a planet axle bore 2111 (see FIGS. 22 and 23)of each shift lever 2106. In one embodiment, the planet axle 2104 has asubstantially uniform diameter over its entire length and has skewrollers 2122 mounted on the opposing end portions 2107. In anotherembodiment, the opposing end portions 2107 include skew roller shoulders(i.e., reduced diameter portions) on which the skew rollers 2122 mount.Each skew roller 2122 can be held in place by a clip ring 2126. The clipring 2126 can be engaged within a groove in the end portions 2107 of theplanet axle 2104. It is disclosed herein that, in some embodiments, ashift lever 2106 can include one or more features such as, for example,a recess, a channel, etc., for providing clearance with other componentsof the CVT 100.

As shown in FIGS. 20-23, in one embodiment, a shift guide roller axle2116 can be engaged within a shift guide roller axle bore 2117 (FIG. 23)of each shift lever 2106 and, optionally, within a corresponding axlecapturing feature (not shown) of the planet axle 2104. Examples of theaxle capturing feature include, but are not limited to, a featuregenerally characterized as a notch, a cut out, a channel, a seat, or thelike. In one embodiment, the shift guide roller axle bore 2117 isgenerally perpendicular to the longitudinal axis L4 of the planet axlebore 2111. The shift guide roller axle bore 2117 is adjacent to a firstend portion 2121 of the shift lever 2106. The shift guide roller axle2116 and the optional axle capturing feature (not shown) can beconfigured for limiting (for example, substantially precluding) radialdisplacement of the shift guide roller axle 2116 with respect to theengaged axle capturing feature. Thus, such mating configuration of theshift guide roller axle 2116 and the optional axle capturing featurelimits displacement of the shift lever 2106 along the longitudinal axisL4 when the shift guide roller axle 2116 is mounted on the planet axle2104 with the shift guide roller axle 2116 engaged within the shiftguide roller axle bore 2117 and the optional axle capturing feature2119. Shift guide rollers 2114 can be mounted on opposing end portionsof each shift guide roller axle 2116. Each shift guide roller axle 2116can be secured in place by, clip rings 2120, which clip rings 2120 canbe engaged within a groove 2191 of the shift guide roller axle 2116 and,optionally, washers.

At a second end portion 2125 of the shift lever 2106, a roller receivingchannel 2129 can be provided. A shift cam roller 2128 is positioned inthe roller receiving channel 2129. A shift cam roller axle 2130 extendsthrough the shift cam roller 2128 and into engagement with axlereceiving passages 2131 (FIG. 23). In one embodiment, the shift camroller axle 2130 can be secured in place through an interference fitwith the respective axle receiving passages 2131. In other embodiments,securing means such as a clip and groove arrangement can be implemented.

Referring to FIG. 20, simultaneous engagement of each planet 2102 (oneshown in FIG. 20) with the first axial force generator subassembly2800A, the second axial force generator subassembly 2800B, and the sun1306 substantially constrains axially and radially the planet 2102 ofeach planet-and-shift-lever subassembly 2100. The planet 2102 isrotatably mounted on the respective planet axle 2104. The skew roller2122 of a planet-and-shift-lever subassembly 2100 is positioned within arespective planet axle passage 1725 (also See FIG. 13) and engages skewroller reaction surfaces 1735 of adjacent shift lever guide flanges1715, thereby substantially precluding rotation of the respectiveplanet-and-shift-lever subassembly 2100 about any radial axis extendingperpendicular to the longitudinal axis L1. The two shift guide rollers2114 of each shift lever 2106 engage respective shift guide rollerreaction surfaces 1740. Accordingly, a first one of the shift guiderollers 2114 engages a shift guide roller reaction surface 1740 on afirst side of the respective planet axle passage 1725, and a second oneof the shift guide rollers 2114 engages a shift guide roller reactionsurface 1740 on a second side of the respective planet axle passage1725. The semi-circular shape of the shift guide roller reactionsurfaces 1740 and the corresponding engagement by the shift guiderollers 2114 serves to, among other things, substantially preclude axialdisplacement of the respective planet-and-shift-lever subassemblies 2100relative to the main axle longitudinal axis L1, as well as to reduce theforce needed to effect a tilting of the planet axles 2104.

Hence, each planet-and-shift-lever subassembly 2100 is substantiallyaxially and radially constrained relative to the main axle longitudinalaxis L1, and constrained with respect to rotation about any radial axisextending perpendicular to the main axle longitudinal axis L1. However,preferably, each planet-and-shift-lever subassembly 2100 is rotatableabout the respective tangential reference axis T1, which extends througha center point of the respective planet 2102 substantially perpendicularto a radial reference axis extending from the main axle longitudinalaxis L1 through the center point of the respective planet 2102.

Referring now to FIGS. 24-29, in one embodiment, the first axial forcegeneratoraxial force generator subassembly 2800A and the secondload-cam-and-traction-ring subassembly 2800B (see FIG. 24) aresubstantially identical in construction and function, and are sometimesreferred to herein generically as the axial force generator subassembly2800. The axial force generator subassembly 2800A can include a load camring 2802, a traction ring 2804A, and a number of load cam rollers 2806.In one embodiment, the load cam ring 2802 is in interlocked engagementwith the housing subassembly 2600, thereby facilitating the transfer oftorque from the housing subassembly 2600 to the load cam ring 2802 byinhibiting unrestricted rotation of the first axial force generatorsubassembly 2800A with respect to the housing subassembly 2600. The loadcam ring 2802 can be configured to transfer torque to the traction ring2804A via the number of load cam rollers 2806. The load cam rollers 2806are engaged between the load cam ring 2802 and the traction ring 2804A.The traction ring 2804B can be positioned between the load cam rollers2806 and the planets 2102. With respect to the first axial forcegenerator subassembly 2800A, torque exerted on the load cam ring 2802 bythe housing subassembly 2600 is transferred from the load cam ring 2802to the traction ring 2804A through the load cam rollers 2806.

As best shown in FIGS. 25-27, in one embodiment, the load cam ring 2802has a generally annular ring shape with a front face 2831 and a rearface 2833. The load cam ring 2802 can include engagement features 2835(for example, peripheral splines) on the front face 2831 that engagemating engagement features of the housing subassembly 2600 (that is, inthe case of the first axial force generator subassembly 2800A) or matingengagement features of the output shaft 2300 (that is, in the case ofthe second axial force generator subassembly 2800B). In one embodiment,a number of bi-directional ramps 2840 can be provided in the rear face2833.

As best shown in FIGS. 28 and 29, in one embodiment, the traction ring2804 has a generally annular ring shape with a front face 2861 and aback face 2863. The traction ring 2804 includes a contact surface 2865that engages the planets 2102 (one shown in FIG. 24). In one embodiment,a number of bi-directional ramps 2870 can be provided in the rear face2863.

The ramps 2840, 2870 can each be configured for receiving one of theload cam rollers 2806 (FIG. 24) to cooperate with the respective loadcam roller 2806 for applying an axial force and a tangential force onthe traction ring 2804A in response to torque being exerted on the loadcam ring 2802. Through such cooperation, torque exerted on the load camring 2802 by the housing subassembly 2600 causes the load cam rollers2806 to urge the traction ring 2804A into compressive engagement withthe planets 2102 and to urge the traction ring 2804A into rotation aboutthe main axle longitudinal axis L1, thereby providing for torquetransfer from the load cam ring 2802 to the planets 2102 via thetraction ring 2804A.

The first traction interface TI1 is the region of contact between thecontact surface 2865 and each one of the planets 2102 (one shown in FIG.24). Through traction at each first traction interface TI1 (See FIG.24), torque imparted to the traction ring 2804A by the load cam ring2802 is transferred to the planets 2102 through engagement of the loadcam rollers 2806 with the ramps 2840, 2870. Such transfer of torquecausing each planet 2102 to rotate about the respective planet axle2104. Preferably, but not necessarily, traction at the first tractioninterfaces TI1 is provided through an elasto-hydrodynamic layer formedby a traction fluid. The traction ring contact surface 2865 is generallyangled relative to the front face 2861, wherein the profile of thecontact surface 2865 mates efficiently with a curvature of each planet2102. The angle of inclination between the front face 2861 and thecontact surface 2865 can be between about 5 degrees and 75 degrees, morepreferably between about 15 degrees and 65 degrees, even more preferablybetween about 30 degrees and 55 degrees, and most preferably betweenabout 35 degrees and 50 degrees.

As disclosed above, in one embodiment, the first axial force generatorsubassembly 2800A and the second axial force generator subassembly 2800Bare substantially identical in construction and function. Accordingly,through traction at each second traction interface TI2 (See FIG. 24) ofthe second axial force generator subassembly 2800B, torque exerted onthe traction ring 2804B by the planets 2102 is transferred from thetraction ring 2804B to the load cam 2802 through the load cam rollers2806. As with the first axial force generator subassembly 2800A,preferably, but not necessarily, traction at the second tractioninterfaces TI2 is provided through an elasto-hydrodynamic layer formedby a traction fluid.

As shown in FIGS. 30-32, in one embodiment, the output shaft 2300includes a neck 2302 and a thrust reaction flange 2304. The neck 2302and the thrust reaction flange 2304 can be generally symmetric about theoutput shaft longitudinal axis L3. The neck 2302 attaches to and extendsfrom a first side 2306 of the thrust reaction flange 2304. The outputshaft 2300 includes a central passage 2308 extending through the neck2302 and the thrust reaction flange 2304 along the longitudinal axis L3.The neck 2302 can include splines 2310 within the central passage 2308for allowing interlocked engagement of the output shaft 2300 to a matingcomponent (for example, a shaft) of a related device, apparatus orsystem. A bearing support surface 2312 of the neck 2302 can extendgenerally parallel to the longitudinal axis L3. A lubricant channel 2314extends between the central passage 2308 and the bearing support surface2312 for providing a lubricant flow path to an output shaft bearingmounted on the bearing support surface 2312. A seal groove 2316 (SeeFIG. 32) such as, for example, an O-ring groove can be provided withinthe central passage 2308. In use, a seal (not shown) seated in the sealgroove 2316 provides a seal between the neck 2302 and the matingcomponent engaged within the central passage 2308 for limiting the flowof lubricant through the interface between the neck 2302 and the matingcomponent. A bearing support surface 2318 and a main axle recess 2320can be provided within the central passage 2308.

The first side of the thrust reaction flange 2304 can be defined by abearing thrust reaction surface 2322 (See FIGS. 31 and 32). A bearingsupport shoulder 2324 extends from the bearing thrust reaction surface2322. A number of engagement features 2326 (for example, splines) andpilot guides 2328 extend from a second side 2330 of the thrust reactionflange 2304 around a periphery of the thrust reaction flange 2304.Mating pairs of the engagement features 2326 and pilot guides 2328 canbe radially aligned and angularly spaced apart around the longitudinalaxis L3. The pilot guides 2328 extend farther from the second side 2330than do the engagement features 2326.

Referring now to FIGS. 30-33, in one embodiment, the output shaft 2300is rotatably mounted on the shoulder 1028 at the first end portion 1006of the main axle 1000. The shoulder 1028 is positioned within thecentral passage 2308. A tip portion of the main axle 1000 can residewithin the main axle recess 2320. A bearing 2332 or other suitabledevice (for example, a roller bearing or bushing) resides between theshoulder 1028 and the bearing support surface 2318. The output shaft2300 circumferentially engages the second axial force generatorsubassembly 2800B in a manner that inhibits unrestricted rotation of thesecond axial force generator subassembly 2800B with respect to theoutput shaft 2300. More specifically, all or a portion of the engagementfeatures 2326 engage adjacent pairs of the engagement features 2835 ofthe load cam ring 2802 with the pilot guides 2328 extending over aperipheral edge of the load cam ring 2802 for helping to maintainalignment of the load cam ring 2802 with the output shaft 2300. Throughsuch inhibiting of unrestricted rotation of the second axial forcegenerator subassembly 2800B with respect to the output shaft 2300,torque can be transferred from the second axial force generatorsubassembly 2800B to the output shaft 2300.

As best shown in FIG. 33, in one embodiment, the housing subassembly2600 includes a first housing cover plate 2605, a second housing coverplate 2610, a central housing shell 2615 and an end cap 2617. Thecentral housing shell 2615 has a generally cylindrical shape. The firsthousing cover plate 2605 attaches to a first end portion 2618 of thecentral housing shell 2615 and the second housing cover plate 2610attaches to a second end portion 2619 of the central housing shell 2615such that the first housing cover plate 2605, the second housing coverplate 2610 and the central housing shell 2615 jointly define an interiorspace 2620 therebetween. The housing cover plates 2605, 2610 can beattached to the central housing shell 2615 by a variety of ways such as,for example, welding, threaded fasteners, mating structural features andthe like. Regardless of the specific method of attaching the housingcover plates 2605, 2610 to the central housing shell 2615, the housingcover plates 2605, 2610 are preferably attached in a manner thatprovides for unrestricted rotation of the housing cover plates 2605,2610 with respect to the central housing shell 2615.

Referring to FIGS. 34-36, in one embodiment, the first housing coverplate 2605 includes a central bore 2620, a bearing recess 2625, a thrustwasher recess 2630, retention device grooves 2631, a peripheral flange2635, and a peripheral shoulder 2640. The first housing cover plate 2605can be generally circular with the bearing recess 2625, the thrustwasher recess 2630, the peripheral flange 2635, and the peripheralshoulder 2640 extending concentrically with respect to a longitudinalaxis L5 of the central bore 2620. The bearing recess 2625 can be inboardof the thrust washer recess 2630 with respect to the central bore 2620.The bearing recess 2625 and the thrust washer recess 2630 are accessiblevia a common side of the first housing cover plate 2605. Mounting holes2637 can be provided in the peripheral flange 2635 such that fastenerscan be extended therethrough for fixedly securing the first housingcover plate 2605 to the central housing shell 2615. In some embodiments,the first housing cover plate 2605 includes only one of the bearingrecess 2625 and the thrust washer recess 2630.

Referring to FIGS. 37-38, in one embodiment, the second housing coverplate 2610 includes a central passage 2650, a bearing recess 2655, athrust washer recess 2660, a peripheral flange 2665, a peripheralshoulder 2670, a number of engagement features 2675, and a number ofpilot guides 2680. In some embodiments, the pilot guides 2680 canprovide retention for a pre-load spring, such as a wave spring. Thesecond housing cover plate 2610 can be generally circular with thebearing recess 2655, the thrust washer recess 2660, the peripheralflange 2665, and the peripheral shoulder 2670 extending concentricallywith respect to a longitudinal axis L6 of the central passage 2650. Thebearing recess 2655 is accessible through an outboard reference face2682 of the second housing cover plate 2610 and the thrust washer recess2660 is accessible through an inboard reference face 2684 of the secondhousing cover plate 2610. The engagement features 2675 (for example,splines) and a number of pilot guides 2680 extend adjacent theperipheral shoulder 2670. Mating pairs of the engagement features 2675and pilot guides 2680 can be radially aligned and angularly spaced apartaround the longitudinal axis L6. The pilot guides 2680 extend fartherfrom the inboard face 2684 than do the engagement features 2675.

Referring now to FIGS. 33-38, in one embodiment, the housing subassembly2600 mounts jointly on the output shaft 2300 and the auxiliary axle1600. Mounted in this manner, the shift-cam-and-sun subassembly 1300,the stator subassembly 1700, the planet-and-shift-lever subassemblies2100 and the axial force generator subassembly 2800A, 2800B are locatedwithin the interior space 2620. The first housing cover plate 2605 isrotatably mounted on the neck 2302 of the output shaft 2300. The firsthousing cover plate 2605 is rotatably mounted on the output shaft 2300and the second housing cover plate 2610 is rotatably mounted on theauxiliary axle 1600.

A bearing 2686 couples between the output shaft neck 2302 and the firsthousing cover plate 2605 for rotatably and radially supporting the firsthousing cover plate 2605 on the output shaft 2300. The bearing 2686resides within the central bore 2308 secured between retention devicessuch as c-clips engaged with the retention device grooves 2631. A ballthrust bearing 2688 couples between the bearing recess 2625 of the firsthousing cover plate 2605 and the bearing support shoulder 2324 forreacting axial loads between the first housing cover plate 2605 and theoutput shaft 2300. Alternatively, in some embodiments, a thrust washer2690 and a thrust needle bearing 2692 couple between the thrust washerrecess 2660 of the of the first housing cover plate 2605 and the bearingthrust reaction surface 2322 of the output shaft 2300 for reacting axialloads between the first housing cover plate 2605 and the output shaft2300.

An axle ball bearing 2694 couples between the second housing cover plate2610, the end cap 2617, and the reaction flange 1605 of the auxiliaryaxle 1600 for reacting radial loads between the second housing coverplate 2610 and the auxiliary axle 1600. The axle ball bearing 2694engages a bearing recess 2655, a bearing support surface 1640 of theauxiliary axle 1600, and a bearing support surface of the end cap 2617.The end cap 2617 is secured to the second housing cover plate 2610through, for example, threaded fasteners (not shown) that extend throughholes in the end cap 2617 and engage mating holes of the second housingcover plate 2610, thereby securing the axle ball bearing 2694 in place.A thrust needle roller bearing 1755 is coupled between the thrustwashers 1757, 1759, which are respectively in contact with the thrustwasher recess 2660 of the second housing cover plate 2610 and a thrustwashers reaction surface 1760 of the stator subassembly 1700. Theauxiliary axle lubricant passages 1630 are aligned with the firstlubricant delivery passage 1024 of the main axle 1000 to allow the flowof lubricant from the shift rod central bore 3026 to the axle ballbearing 2694, thrust bearing 1755, and optionally subsystem componentsadjacent to the reaction flange 1605 and/or the axle ball bearing 2694.

The second housing cover plate 2610 circumferentially engages the firstaxial force generator subassembly 2800A in a manner that inhibitsunrestricted rotation of the first axial force generator subassembly2800A with respect to the housing subassembly 2600. More specifically,all or a portion of the engagement features 2326 engage adjacent pairsof the engagement features 2835 of the load cam ring 2802 with the pilotguides 2328 extending over a peripheral edge of the load cam ring 2802for helping to maintain alignment of the load cam ring 2802 with thesecond housing cover plate 2610. Through such inhibiting of unrestrictedrotation of the second axial force generator subassembly 2800B withrespect to the second housing cover plate 2610, torque can betransferred to the second axial force generator subassembly 2800B fromthe second housing cover plate 2610.

As best shown in FIGS. 39-41, in one embodiment, the lubricant manifold2700 includes a central bore 2705, a flange 2710, a lubricant channel2715, a piloting recess 2720, an engagement hub 2725, bore seal grooves2730 and a flange seal groove 2735. The central bore 2705 can belongitudinally aligned with the piloting recess 2720 with the bore sealgroove 2730 being concentric with the central bore 2705. The lubricantchannel 2715 intersects the central bore 2705 thereby allowing fluidcommunication therethrough. The lubricant channel 2715 can intersect thecentral bore 2705 at a position between the bore seal grooves 2730. Insome embodiments the lubricant channel can be provided in a lubricantboss 2711 that is located on one side of the flange 2710. The engagementhub 2725, which serves to pilot/align the lubricant manifold withrespect to a mating structure, can have a circular cross-sectional shapeand be concentric with respect to the central bore 2705. Examples ofsuch a mating structure include, but are not limited to, a housing orcase of an engine, transmission, motor and the like. Fastener holes 2732can extend through the flange 2710 for allowing the flange 2710 to befixedly engaged with the mating structure. The flange seal groove 2735is formed in an engagement face 2736 of the flange 2710. The flange sealgroove 2735 is configured for carrying a seal (for example, an O-ringseal) for providing a liquid and/or contaminant resistant seal betweenthe flange 2710 and the mating structure. The piloting recess 2720extends through a reaction surface 2737 of the engagement hub 2725 andhas a rectangular cross-sectional profile that allows the pilotingrecess 2720 to engage the auxiliary axle second shoulder 1615 in aninterlocked and/or indexed manner. A main axle reaction surface 2740 canbe provided at a first end portion 2745 of the central bore 2705 forsupporting a mating end portion of the main axle 1000.

Referring now to FIGS. 39-42, in one embodiment, the lubricant manifold2700 mounts jointly on the auxiliary axle 1600 and the main axle 1000.The piloting recess 2720 supportably engages the auxiliary axle secondshoulder 1615 and the main axle reaction surface 2740 supportablyengages the third segment 1018 of the main axle 1000. The engagement hub2725 engages the axle ball bearing 2694 for reacting axial loads exertedon the axle ball bearing 2694 by the stator subassembly 1700. A mainaxle nut 1040 engages the main axle treads 1012 and exerts an axial loadon the lubricant manifold 2700 such that the auxiliary axle 1600, thestator subassembly 1700 and the lubrication manifold 2700 are axiallyconstrained between the axial reaction flange 1003 and the main axle nut1040. In some embodiments, the main axle nut 1040 can facilitate theapplication of a preload to the bearing 2694. A lubricant port 2750engages within the lubricant channel 2715. The lubricant channel 2715aligns with the main axle lubricant inlet passage 1026, thereby allowinglubricant supplied through the lubricant port 2750 to flow into theshift rod central bore 3026. Accordingly, the spaced apart bore sealgrooves 2730 engage the main axle 1000 on opposing sides of thelubricant inlet passage 1026.

In operation (referring to FIG. 42), the lubricant manifold 2700receives lubricant via the lubricant port 2750. From the lubricant port2750, lubricant flows from lubricant channel 2715 through the lubricantinlet passage 1026 and the slot 3010 into the shift rod central bore3026. A plug (not shown) within the central bore 3026 at the distal end3042 of the shift rod 3000 limits the flow of lubricant from the shiftrod central bore 3026 at the distal end 3042. From the central bore3026, lubricant flows through the shift rod 3000 to the lubricant ports3015 of the shift rod 3000 and into one or both of the lubricantchannels 1318 of the shift cam extension 1310. The lubricant lubricatesthe shift cam thrust bearings 1308 and, after exiting via the spacebetween the shift cam bodies 1302, 1304 and the sun 1306, lubricates theplanet assemblies 2100. In one embodiment, lubricant pressure at thelubricant port 2750 is about 7 psi and 1 gpm.

Referring to FIGS. 43-45, an embodiment of a drivetrain casing 3700 isshown. The drivetrain casing is one example of the mating structurereferred to above. The drivetrain casing 3700 is specifically configuredfor the CVT 100 discussed above into a driveline of a vehicle betweenthe prime mover and the remaining downstream driveline components.Additionally, in some embodiments, the drivetrain casing 3700 is adaptedto allow integration of the CVT 100 with a vehicle chassis or a primemover structure. Examples of a vehicle chassis structure include, butare not limited to a vehicle frame and a vehicle uni-body. Examples of aprime mover structure include, but are not limited to an engine block,an engine casing and a motor housing.

A main body 3702 of the drivetrain casing 3700 includes a transmissionmounting portion 3704 to which the flange 2710 of the CVT 100 (See FIGS.39-42) can be fastened. The mounting portion 3704 includes a mountingsurface 3706 configured for being engaged with the flange engagementface 2736 (See FIGS. 40-42). The mounting surface 3706 includes acentral passage 3708 configured for piloting the lubrication manifoldengagement hub 2725. Fasteners (not shown) extend jointly throughrespective fastener holes 3710, 2732 for fixedly securing the flange2710 to the mounting portion 3704. In this mounted arrangement, thelubrication manifold 2700 and the distal end 3042 of the shift rod 3000are external to an interior space 3712 of the main body 3702, with thehousing subassembly 2600 and CVT components engaged therewith beinglocated within the interior space 3712.

The drivetrain casing main body 3702 is configured for fixedly securingto a mating portion of a vehicle chassis structure or a prime moverstructure. In one embodiment, the main body 3702 includes fastenerbosses 3714 that are each configured for receiving a fastener (forexample, a threaded bolt or threaded screw). Through engagement of eachfastener with a respective engagement portion of the vehicle chassisstructure or a prime mover structure (for example, treaded holes),fasteners extending through the fastener bosses 3714 secure thedrivetrain casing 3700 to the vehicle chassis structure or a prime moverstructure.

In one embodiment, the drivetrain casing 3700 includes a lubricant sumpcavity 3716. The lubricant sump cavity 3716 is a partially separatedspace from the main body interior space 3712 and includes an edgeportion 3718 that is configured for being engaged by a sump cavity coverplate (not shown). Through sealed engagement of the sump cavity coverplate with the edge portion 3718, the lubricant sump cavity 3716 and thesump cavity cover plate jointly define a sump chamber in which lubricantcan be contained and extracted by a sump pump (not shown) that supplieslubricant to the lubricant manifold 2700. It is disclosed herein thatthe sump cavity cover plate can be replaced by a wall that is unitarilyformed with the drivetrain casing 3700, with a lubricant fill plugopening and/or lubricant drain plug opening being provided forfacilitating filling the sump chamber with lubricant and/or drainingremoving lubricant from the sump chamber. It is further disclosed hereinthat the drivetrain casing 3700 and/or the sump cavity cover plate caninclude cooling fins for dissipating heat.

Referring to FIGS. 46-48, an embodiment of an infinitely variabletransmission (IVT) 4200 is shown. The IVT 4200 is particularly suitablefor, among other applications, vehicles such as a tractor or other typeof load-carrying commercial/industrial vehicle. In use, the IVT 4200couples between a prime mover (for example, a gas powered engine, motoror the like) and a load (for example an axle assembly) for varyingtorque applied from the prime mover to the load, or for controlling thespeed ratio between the prime mover and the output. As discussed belowin greater detail, components of the IVT 4200 are arranged andinterconnected in a manner that facilitates the infinitely variabletransmission (IVT) 4200 can include one or more of the variouscomponents and subassemblies that are essentially or identically thesame as that discussed above in reference to FIGS. 1-45. In such cases,discussion of those essentially or identically the same componentsand/or subsystems will be limited to that necessary to sufficientlydescribe how these components and/or subsystems are implemented withinthe IVT 4200. Where components and/or subsystems are implemented in theIVT 4200, reference numbers for those components and/or subsystems willbe the same as those used above in FIGS. 1-45.

Still referring to FIGS. 46-48, an input shaft 4202 supports theshift-cam-and-sun subassembly 1300 discussed in reference to the CVT100. The shift-cam-and-sun subassembly 1300 is supported by the inputshaft 4202 in a manner allowing translation of the shift-cam-and-sunsubassembly 1300 along a longitudinal axis L21 of the input shaft 4202.The input shaft 4202 supports an auxiliary axle 4600 in a manner thatcoincidentally aligns a longitudinal axis L22 of the auxiliary axle 4600with the input shaft longitudinal axis L21 and that inhibitsunrestricted relative rotation of the auxiliary axle 4600 with respectto the input shaft 4202. The auxiliary axle 4600 is generally the sameconfiguration as the auxiliary axle 1600 with the exception that theauxiliary axle 1600 includes the second shoulder 1615 whereas theauxiliary axle 4600 does not include a second shoulder. The input shaft4202 and the auxiliary axle 4600 jointly support the stator subassembly1700 discussed above in reference to the CVT 100. The stator subassembly1700 is supported such that the centerline axis C1 of the statorsubassembly 1700 extends coincidentally with the input shaftlongitudinal axis L21.

The number of planet-and-shift-lever subassemblies 2100 discussed abovein reference to the CVT 100 is arrayed angularly around the input shaftlongitudinal axis L21 and is supported jointly by the shift-cam-and-sunsubassembly 1300 and the stator subassembly 1700. The input shaft 4202supports the output shaft 2300 discussed above in reference to the CVT100. Bearings 2686, 2688, and 2332 rotatably support the output shaft2300 between the input shaft 4202 and the housing subassembly 5600 in amanner such that a longitudinal axis L23 of the output shaft 2300extends coincidentally with the input shaft longitudinal axis L21.

The output shaft 2300 and the auxiliary axle 4600 jointly support ahousing subassembly 5600. The housing subassembly 5600 is supported in amanner that coincidentally aligns a centerline axis C22 of the housingsubassembly 5600 with the input shaft longitudinal axis L21 and allowsrelative rotation of the housing subassembly 5600 with respect to outputshaft 2300 and the auxiliary axle 4600. A shift actuation subassembly5900 mounts on the input shaft 4202 in a manner allowing selectcomponents of the shift actuation subassembly 5900 to rotate with theinput shaft 4202 while other components of the shift actuationsubassembly 5900 are held stationary and/or allowed to rotateindependent from rotation of the input shaft 4202. The shift actuationsubassembly 5900 is coupled to the shift-cam-and-sun subassembly 1300through a shift rod 6000 for facilitating selective translation of theshift-cam-and-sun subassembly 1300 along the input shaft longitudinalaxis L21. A lubricant manifold 5700 is jointly supported by the housingsubassembly 5600, the shift actuation subassembly 5900 and a bearing4208 in a manner whereby the lubricant manifold 5700 is held stationarywith respect to rotation of the input shaft 4202. A lubricant sump body6300 mounts on the housing subassembly 5600 thereby providing a sumpchamber 6205 in which a supply of lubricant can be maintained.

With respect to the IVT 4200, the stator subassembly 1700 and theplanet-and-shift-lever subassemblies 2100 can be configured and interactin the same manner discussed above in reference to the CVT 100.Accordingly, the planet-and-shift-lever subassemblies 2100 can besynchronously rotated for facilitating torque ratio adjustment. Throughsuch synchronous rotation, all of the planet-and-shift-leversubassemblies 2100 are in the same relative rotational position at agiven point in time. Furthermore, it is disclosed herein that the statorsubassembly 1700 can be secured to the input shaft 4202 and/or theauxiliary axle 4600 by any suitable fastening method. Examples of suchsuitable fastening methods include, but are not limited to, interferencepress fit, threaded fastener and mating threaded holes, keyedengagement, splined engagement, etc. For example, one or both of thestators 1705A, 1705B can be secured using screws that engage matingthreaded holes (not shown) of the input shaft 4202 and/or the auxiliaryaxle 4600.

Referring now to FIG. 48, in one embodiment, the first axial forcegenerator subassembly 2800A discussed above in reference to the CVT 100couples between the housing subassembly 5600 and the planets 2102, andthe second axial force generator subassembly 2800B discussed above inreference to the CVT 100 couples between the output shaft 2300 and eachone of the planets 2102. The first axial force generator subassembly2800A couples to the housing subassembly 5600 in a manner inhibitingunrestricted relative rotation of the first axial force generatorsubassembly 2800A with respect to the housing subassembly 5600. Thesecond axial force generator subassembly 2800B couples to the outputshaft 2300 in a manner inhibiting unrestricted relative rotation of thesecond axial force generator subassembly 2800B with respect to theoutput shaft 2300. The first axial force generator subassembly 2800A,the second axial force generator subassembly 2800B and theshift-cam-and-sun subassembly 1300 jointly locate each one of theplanets 2102 in a manner that inhibits their axial translation andconstrains their angular translation about a respective reference axisT21, which extends through the center of the planets 2102perpendicularly with respect to the input shaft 4202.

During operation of the IVT 4200, torque exerted on the input shaft 4202causes the input shaft 4202 and the stator subassembly 1700 to jointlyrotate about the input shaft longitudinal axis L21. The statorsubassembly 1700 supports the planet-and-shift-lever subassemblies 2100in a manner that inhibits unrestricted relative rotation of theplanet-and-shift-lever subassemblies 2100 with respect to the statorsubassembly 1700. Accordingly, the planet-and-shift-lever subassemblies2100 rotate together with the input shaft 4202 and the statorsubassembly 1700. The lubricant manifold 5700, the housing subassembly5600, the lubricant sump body 6200, and portions of the shift actuationsubassembly 5900 are held stationary with respect to rotation of theinput shaft 4202. Through traction at a respective first tractioninterface TI21 between the input axial force generator subassembly 2800Aand each planet 2102, torque is exerted by the first axial forcegenerator subassembly 2800A on the planets 2102, thereby causing eachplanet 2102 to rotate about a respective planet longitudinal axis L4.The first traction interface TI21 is defined, as used here, as a regionof contact between the first axial force generator subassembly 2800A andthe respective planet 2102. The interaction between the first-axialforce generator subassembly 2800A and the planets 2102 causes theplanet-and-shift-lever subassemblies 2100 to orbit about thelongitudinal axis L23. Through traction at a respective second tractioninterface TI22 between the second axial force generator subassembly2800B and each planet 2102, torque is exerted by the planets 2102 on thesecond axial force generator subassembly 2800B, thereby causing thesecond axial force generator subassembly 2800B and output shaft 2300 tojointly rotate about the output shaft longitudinal axis L23. The secondtraction interface TI22 is defined, as used here, as a region of contactbetween the second axial force generator subassembly 2800B and therespective planet 2102.

Turning now to a brief discussion of power flow through the IVT 4200 andstill referring to FIG. 48, torque is delivered to the IVT 4200 throughthe input shaft 4202 such as via a sprocket or hub fixedly mounted onthe input shaft 4202. The exertion of torque on the input shaft 4202urges the input shaft 4202 and the stator subassembly 1700 to rotateabout the input shaft longitudinal axis L21. Because theplanet-and-shift-lever subassemblies 2100 are supported by the statorsubassembly 1700 in a manner that inhibits unrestricted rotation of theplanet-and-shift-lever subassemblies 2100 with respect to the statorsubassembly 1700, rotation of the input shaft 4202 causes orbiting ofthe planet-and-shift-lever subassemblies 2100 about the input shaftlongitudinal axis L21. In view of the first axial force generatorsubassembly 2800A being precluded from rotating about the input shaftlongitudinal axis L21 through its coupling to the housing subassembly5600, traction between the first axial force generator subassembly 2800Aand each planet 2102 at the respective first traction interface TI21causes the planets 2102 to rotate about their respective longitudinalaxis L4 in response to rotation of the input shaft 2300. In such anembodiment, the planets 2102 rotate about their respective longitudinalaxis L4 in direction that is rotationally opposite the direction ofrotation of the input shaft 4202. In response to rotation of the planets2102, the planets 2102 transfer torque to the second axial forcegenerator subassembly 2800B via the respective second traction interfaceTI22. The second axial force generator subassembly 2800B exerts torqueon the output shaft 2300 thereby urging the output shaft 2300 to rotateabout the output shaft longitudinal axis L23.

Presented now is a brief description of torque ratio variationfunctionality provided by an Infinitely Variable Transmission (IVT) inthe context of the disclosures made herein (for example, the IVT 4200).Such IVT functionality, like the CVT functionality described above inreference to the CVT 100, allows essentially every fractional ratiowithin a given range to be selected in a continuous manner as opposed toa discrete or stepped manner. However, in addition to allowingessentially every fractional torque ratio within a given range to beselected in a continuous manner, IVT functionality also allows deliveryof a zero output speed (a “powered zero” state) with a non-zero inputspeed of a power delivery device (for example, constant speed of asprocket attached to the input shaft 4202 of the IVT 4200). Hence, giventhe definition of torque ratio as the ratio of input torque to outputtorque, an IVT in the context of the disclosures made herein is (atleast theoretically) capable of delivering an infinite set of torqueratios.

For a given IVT construction, power input rotational direction withrespect to power output rotational direction is variable. That is, for agiven power input rotational direction, torque ratio adjustment canresult in power output rotational direction being the same or oppositethe given power input rotational direction. The zero output speeddiscussed above is present at the adjustment position where the inputand output rotational directions transition between being the same andbeing opposite. For example, referring to the IVT 4200 and FIG. 48, aconstant rotational speed of the input shaft 4202 in a given directionand the non-rotating arrangement of the first axial force generatorsubassembly 2800A and traction at the respective first tractioninterface TI21 of each planet 2102 causes the planets 2102 to rotateabout the longitudinal axis L4 at a constant rotational speed. Thesurface speed, relative to the longitudinal axis L4, at the firsttraction interface TI21 of a planet 2102 is a function of orbital speedof the planet 2102 and the perpendicular distance from the firsttraction interface TI21 to the planet longitudinal axis L4.

With the planet-and-shift-lever subassemblies 2100 adjusted with theirrespective longitudinal axis L4 extending parallel to the longitudinalaxis L21 of the input shaft 4202 (as shown in FIG. 48), the rotationalspeed and the orbital speed at the second traction interfaces TI22 ofall the planets 2102 is the same as the surface speed at the firsttraction interfaces TI21 (that is, zero surface speed). With theplanet-and-shift-lever subassemblies 2100 adjusted in this orientation,the IVT 4200 is in the “powered zero” state. The “powered zero” stateexists in this orientation because while the input speed and torque(that is, power) provided by the input shaft 4202 is nonzero, the outputspeed at the second axial force generator subassembly 2800B is zero.Moreover, coupling of the second axial force generator subassembly 2800Bto the output shaft 2300 dictates that the output shaft 2300 remainsstationary as well.

Still referring to the IVT 4200 and FIG. 48 while still assuming thatthe rotational speed of the input shaft 4202 is being maintainedconstant, adjustment of the planet-and-shift-lever subassemblies 2100(that is, rotation about the reference axis T21) causes a reduction orincrease in the perpendicular distance between the first tractioninterface TI21 and the planet longitudinal axis L4 of each planet 2102.This reduction or increase in the perpendicular distance causes aproportional and respective reduction or increase in the rotationalspeed of the planets 2102, which causes a proportional and respectivereduction or increase in the surface speed at the second tractioninterface TI22 of each planet 2102. Under the assumption that there isnegligible or limited slippage between the planets 2102 and the secondaxial force generator subassembly 2800B, the planets 2102 apply aproportional rotational force on the second axial force generatorsubassembly 2800B. Because the orbital speed of the planets 2102 and therotational speed of the planets 2102 are in opposite rotationaldirections, when the effect of the orbital speed of the planets 2102 isgreater than the effect of the rotational speed of the planets 2102 onthe resulting surface speed of the planets 2102, the planets 2102 urgethe second axial force generator subassembly 2800B to rotate in the samedirection as the input shaft 4202 is rotating. Conversely, when theeffect of the orbital speed of the planets 2102 is smaller than theeffect of the rotational speed of the planets 2102 on the resultingsurface speed of the planets 2102, the planets 2102 urge the secondaxial force generator subassembly 2800B to rotate in the oppositedirection as the input shaft 4202 is rotating. Accordingly, it can beseen that torque ratio adjustment of an IVT in accordance with thedisclosures made herein provides for reversal of output shaft rotatingdirection with respect to a constant input shaft rotating direction.Hence, in some embodiments, IVT functionality of the IVT 4200 isachieved without the use of auxiliary gearing, coupling, or clutching.That is, in some embodiments, merely through adjustment of the tilt ofthe planets 2102, the IVT 4200 can produce a change from a positiverotation, to zero rotation, to a negative rotation. It should be notedthat a load or prime mover cannot back drive the output shaft 2300 atthe powered zero state because the first axial force generatorsubassembly 2800A is coupled to ground (that is, the subassembly 2800Ais nonrotatable relative to the longitudinal axis L23).

It should be noted that some transmissions use a continuously variablevariator unit (for example a CVT) coupled to other gearing and/orclutches to produce IVT functionality. Usually, in such transmissions,power is diverted from a mixing device, routed through the CVT section,and summed back to the original power path at some node in thetransmission. In such an arrangement, recirculating power can be greaterthan the throughput power and can significantly decrease the efficiencyof the transmission. Many of the inventive embodiments described hererequire no split powered arrangement to achieve IVT functionality. Inthe context of the disclosures presented herein, IVT functionality suchas that provided by the IVT 4200 is preferably understood as providingIVT functionality without being necessarily coupled to additionalgearing, clutches, split powered arrangements, and/or other devices.

Returning now to discussing construction and elements of the IVT 4200,as best shown in FIGS. 49-51, one embodiment of the input shaft 4202 canbe configured for having the shift-cam-and-sun subassembly 1300, theauxiliary axle 4600, the stator subassembly 1700, the housingsubassembly 5600, and the lubricant manifold 5700 axially constrainedbetween an axial reaction flange 4206 thereof and a bearing 4208. Thebearing 4208 is axially constrained between the lubrication manifold5700 and a retention device 4210 engaged with a respective retentiondevice groove of the input shaft 4202. The axial reaction flange 4206can be fixedly attached to a first end portion 4212 of the input shaft4202.

The input shaft 4202 includes various structural features configured forengaging mating components of subassemblies and/or related fasteningdevices. In one embodiment, the input shaft 4202 includes a firstsegment 4213 of a first diameter, a second segment 4214 of a seconddiameter, a third segment 4216 of a third diameter, a fourth segment4218, a fifth segment 4219 of a fifth diameter, a first slot 4220, afirst locking member seat 4222 (for example, a recess configured forreceiving a key), a second slot 4224, a second locking member seat 4225,a lubricant inlet passage 4226, a lubricant delivery passage 4228, and aretention device groove 4229. The first segment 4213 can extend from aninboard face 4229 of the axial reaction flange 4206, with the secondsegment 4214 extending from the first segment 4213, the third segment4216 extending from the second segment 4214, the fourth segment 4218extending from the third segment 4216, and the fifth segment 4219extending from the fourth segment 4218. In this manner, the input shaftsegments 4213-4219 can define respective shoulders on which variouscomponents and/or subassemblies can be mounted.

The first end portion 4212 of the input shaft 4202 can include ashoulder 4230 extending from an outboard face 4231 of the axial reactionflange 4206 for supporting a bearing 4232 and can have a recess 4233therein to provide for receiving a plug 4233 adapted to contain a spring(not shown) within a longitudinal passage 4236 of the input shaft 4202.The bearing 4232 serves to rotatably support the output shaft 2300 onthe input shaft 4202. The spring and plug arrangement can be configuredto bias the shift rod 6000 to a prescribed position. The first lockingmember seat 4222 is configured for receiving a retention device (forexample, a key) that also engages a mating retention feature (forexample, slot) of the auxiliary shaft 4600 for inhibiting unrestrictedrotation of the auxiliary shaft 4600 with respect to the input shaft4202. The second locking member seat 4225 is configured for engaging aretention device that also engages a mating structure (for example slot)of a power input means (not shown) such as, for example, a pulley, gear,sprocket, etc.

In one embodiment, a longitudinal passage 4236 of the input shaft 4202extends along the longitudinal axis L1 between the end portions 4212,4239. The longitudinal passage 4236 can be configured for having theshift rod 6000 slidably disposed therein. The slot 4220, 4224, thelubricant inlet passage 4226, and the lubricant delivery passage 4228each extends communicatively between a respective exterior face of theinput shaft 4202 and the longitudinal passage 4236 for allowingrespective structural interconnection and/or providing a respectivelubricant flow path.

As best shown in FIGS. 52 and 53, in one embodiment, the shift rod 6000includes an elongated, generally round body 6005. The body 6005 includesa slot 6010, lubricant passages 6015, a first coupling device passage6020, a second coupling device passage 6025, a central bore 6026, a sealgroove 6030, and a piloting stub 6035. The central bore 6026 can extendpartially from a first end portion 6040 of the body 6005 toward a secondend portion 6045 or, alternatively, along the entire length. The slot6010, the lubricant passages 6015, and the coupling device passages 6020extend from an exterior surface of the elongated tubular body 3005 tothe central bore 6026. The piloting stub engages a spring (not shown).This spring together with the spring (not shown) within the input shaftlongitudinal passage 4236 can serve to bias or assist in moving theshift rod 6000 toward a particular position such as, for example, aposition corresponding to a particular torque ratio.

Referring to FIGS. 52-54, the shift rod 6000 can be slidably engagedwithin the input shaft longitudinal passage 4236 for affectingsynchronous rotation of the planet-and-shift-lever subassemblies 2100. Acoupling device 6060 such as a roll pin couples the shift rod 6000 tothe shift-cam-and-sun subassembly 1300. The coupling device 6060 extendsthrough the coupling device passage 6020 and fixedly engages thecoupling member holes 1316 (see FIG. 16) of the shift-cam-and-sunsubassembly 1300 such that axial translation of the shift rod 6000causes a corresponding axial translation of the shift-cam-and-sunsubassembly 1300. Through engagement of the shift-cam-and-sunsubassembly 1300 with all of the planet-and-shift-lever subassemblies2100, translation of the shift-cam-and-sun subassembly 1300 causes allof the planet-and-shift-lever subassemblies 2100 to synchronously rotatethe about the respective axis T1, thereby resulting in an adjustment ofthe torque ratio. The slot 6010 allows lubricant to flow from thelubricant manifold 2700 into the central bore 6026 with the shift rod6000 at various translated positions. The lubricant passages 6015 allowlubricant to flow from the central bore 6026 to the shift-cam-and-sunsubassembly 1300 via the slot 4220 of the input shaft 4202 and thelubricant passage 1318 of the shift-cam-and-sun subassembly 1300.

Referring to FIGS. 54-60, in one embodiment, the shift actuationsubassembly 5900 includes a shift pin collar 5902, a shift nut 5904, ashift screw 5906, a control plate 5908, a shift screw bearing 5910, anda coupling device 5912. The shift pin collar 5902 includes a centralbore 5911 through which the fourth segment 4218 of the input shaft 4202extends. The coupling device 5912 extends through the second couplingdevice passage 6025 of the shift rod 6000 and the second slot 4224 ofthe input shaft 4202 into fixed engagement with coupling device holes5914 of the shift pin collar 5902. The central bore 5911 and the inputshaft fourth segment 4218 are jointly configured such that the shift pincollar 5902 is translatable along the input shaft longitudinal referenceaxis L21. For example, in one embodiment, the central bore 5911 and theinput shaft fourth segment 4218 are jointly dimensioned to provide aclose tolerance clearance fit. Accordingly, translation of the shift pincollar 5902 along the input shaft 4202 causes a correspondingtranslation of the shift-cam-and-sun subassembly 1300 along the inputshaft 4202.

The shift screw 5906 rotationally engages the shift pin collar 5902 andengages the shift nut 5904, which mounts on a mating structure of thelubricant manifold 5700 in a manner that limits, if not inhibits,relative rotation and translation therebetween. For example, in oneembodiment, a press fit interface is provided between a central bore5917 of the shift nut 5904 and the mating structure of the lubricantmanifold 5700, which precludes the shift nut 5904 from relative rotationor translation with respect to the engaged mating structure. The shiftscrew bearing 5910 is coupled between the shift pin collar 5902 and theshift screw 5906 for allowing the shift pin collar 5902 to rotateindependently from the shift screw 5906. With respect to the shift screw5906 (See FIGS. 54, 58 and 59), the shift screw bearing 5910 mountswithin a recess 5916 and is captured between a shoulder 5918 and aretention device 5922 engaged within a groove 5920. With respect to theshift pin collar 5902 (See FIG. 54-56), the shift screw bearing 5910mounts on a neck 5924 and is captured between a shoulder 5926 and theretention device 5922, which is engaged within a groove 5928.Constrainment of the shift screw bearing 5910 in this manner inhibitsunrestricted translation of the shift screw 5906 relative to the shiftpin collar 5902.

Threads 5930 of the shift nut 5904 engage threads 5932 of the shiftscrew 5906. Rotation of the shift screw 5906 causes the shift screw 5906to thread in or thread out of the shift nut 5904, resulting incorresponding translation of the shift screw 5906 along the input shaftlongitudinal reference axis L21. Accordingly, due to constrainment ofthe shift screw 5906 with the shift pin collar 5902, the shift pincollar 5902 translates essentially in unison with the shift screw 5906as does the shift rod 6000 and shift-cam-and-sun subassembly 1300. Inthis manner, the torque ratio can be adjusted through rotation of theshift screw 5906. The control plate 5908 can be attached to the shiftscrew 5906 such as through press fit interference between a central bore5934 of the control plate 5908 and a shoulder 5936 of the shift screw5906. In one embodiment, the shift screw 5906 includes a reaction flange5014 adapted to react and/or locate the control plate 5908. In thismanner, an external adjustment mechanism can be connected to the controlplate 5908 such as via the one of more holes 5938 for allowing theexternal adjustment mechanism to control rotation of the shift screw5906 and, thereby, control adjustment of the torque ratio.

As best shown in FIGS. 61-63, in one embodiment, the lubricant manifold5700 can include a central bore 5705, a flange 5710, a lubricant channel5715, a bearing pocket 5720, an engagement shoulder 5725, bore sealgrooves 5730, a flange seal groove 5735, and a recess 5737. The centralbore 5705, the bearing pocket 5720, and the bore seal groove 5730 areaxially aligned and concentric with respect to each other. The bore sealgrooves 5730 can be provided within the central bore 5705. The lubricantchannel 5715 intersects the central bore 2705 thereby allowing fluidcommunication therethrough. The lubricant channel 5715 can intersect thecentral bore 5705 at a position between the bore seal grooves 5730. Theengagement shoulder 5725, which serves as the mating structure of thelubricant manifold on which the shift nut 5904 is mounted, can have acircular cross-sectional shape and be concentric with respect to thecentral bore 5705. Fastener holes 5740 can extend through the flange5710 for allowing the flange 5710 to be fixedly engaged with the housingsubassembly 5600. The flange seal groove 5735 is formed in an engagementface 5745 of the flange 5710. In one embodiment, the flange seal groove5735 is configured for carrying a seal (for example, an O-ring seal) forproviding a liquid and/or contaminant resistant seal between the flange5710 and the housing subassembly 5600.

Referring now to FIGS. 61-64, in one embodiment, the lubricant manifold5700 interfaces with the input shaft 4202 through the bearing 4208,which is captured within the bearing pocket 5720, and is fixedly securedto the housing subassembly 5600 by threaded fasteners (not shown) thatextend through the mounting holes 5740 into threaded engagement withmating holes of the housing subassembly 5600. The recess 5737 providesfor clearance between the lubricant manifold 5700 and the auxiliary axle4600. Interaction of the lubricant manifold 5700 with the input shaftthrough the bearing 4208 allows rotation of the input shaft 4202 withrespect to the lubricant manifold 5700. The lubricant channel 5715aligns with the lubricant inlet passage 4226 of the input shaft 4202,thereby allowing lubricant supplied through the lubricant channel 5715to flow into the shift rod central bore 3026. Accordingly, seals (notshown) within the spaced apart bore seal grooves 5730 engage the inputshaft 4202 on opposing sides of the lubricant inlet passage 4226 betweenthe input shaft 4202 and the lubricant manifold 5700.

As shown in FIG. 64, in one embodiment, the housing subassembly 5600includes a first housing cover plate 5605, a second housing cover plate5610, and a central housing shell 5615. The second housing cover plate5610 and the central housing shell 5615 are constructed andinterconnected essentially the same as the second housing cover plate2610 and the central housing shell 2615 discussed above in reference tothe CVT 100. The first housing cover plate 5605 attaches to the centralhousing shell 5615 in essentially the same manner as the first housingcover plate 2605 attaches to the central housing shell 2615 discussedabove in reference to the CVT 100. Furthermore, the housing subassembly5600 engages the input shaft 4202 and auxiliary axle 4600 in theessentially the same manner as the housing subassembly 2600 mounts onthe main axle 1000 and the auxiliary axle 1600 discussed above inreference to the CVT 100. Accordingly, the second housing cover plate5610 and the central housing shell 5615 will not be discussed in furtherdetail, nor will attachment of the first housing cover plate 5605 to thecentral housing shell 5615 or mounting of the housing assembly 5600 onthe input shaft 4202.

Referring to FIGS. 64-66, in one embodiment, the first housing coverplate 5605 includes a central bore 5620, a bearing recess 5630,retention device grooves 5631, a peripheral flange 5635, a peripheralshoulder 5640, and lubricant channels 5643. The first housing coverplate 5605 can be generally circular with the bearing recess 5630, theperipheral flange 5635, and the peripheral shoulder 5640 extendingconcentrically with respect to the longitudinal axis of the central bore5620. Mounting holes 5646 can be provided in the peripheral flange 5635such that fasteners can be extended therethrough to fixedly secure thefirst housing cover plate 5605 to the central housing shell 5615. Thelubricant channels 5643 allow lubricant to drain from within the housingsubassembly 5600.

As shown in FIGS. 67-69, in one embodiment, the lubricant sump 6300includes a body 6302. The body 6302 includes chassis mounting holes6305, housing mounting holes 6310, lubricant passages 6315, a lubricantcavity 6320, a central bore 6325, and a seal pocket 6330. The lubricantcavity 6320, the central bore 6325, and the seal pocket 6330 arepreferably, but not necessarily, generally concentric. The lubricantpassages 6315 extend from an exterior surface of the body 6302 to thelubricant cavity 6320 for allowing the flow of lubrication therethrough.The seal pocket 6330 is configured for receiving a seal therein tofacilitate providing a seal with a power transfer shaft of a load (notshown) coupled with the splines 2310 of the output shaft 2300.

The chassis mounting holes 6305 can be positioned adjacent an exteriorperimeter edge portion of the body 6302 and can be configured forreceiving fasteners therein to secure the lubricant sump to a supportstructure (for example, a chassis, housing, block and/or case of avehicle, an engine, a transmission, a motor, a differential, a powertake-off unit and/or the like). The housing mounting holes 6310 can bepositioned uniformly around the lubricant cavity 6320 and can beconfigured for receiving fasteners therein to secure the body 6302 tothe housing subassembly 5600. For example, the mounting holes 6310 canbe arranged to align with all or a portion of the mounting holes 5646 ofthe first housing cover plate 5605 such that the same fasteners fastenthe body 6302 and the first housing cover plate 5605 to the centralhousing shell 5615 of the housing subassembly 5600.

In operation (referring to FIG. 64), lubricant is supplied to thelubricant manifold 5700 through the lubricant channel 5715 by a pump(not shown). From the lubricant channel 5715, lubricant flows throughthe lubricant inlet passage 4226 and the slot 6010 into the central bore6026 of the shift rod 6000. From the central bore 6026, lubricant flowsthrough the shift rod 6000 to lubricant ports 6015 of the shift rod 6000and into one or both of the lubricant channels 1318 of the shift camextension 1310. The lubricant lubricates the shift cam thrust bearings1308 and, after exiting via the space between the shift cam bodies 1302,1304 and the sun 1306, lubricates the planets 2102. Lubricant flowsthrough the lubricant channels 5643 in the first cover plate 5605 andcollects in the lubricant sump 6300. Lubricant is then recirculated fromthe lubricant sump 6300 to the lubricant manifold 5700.

Referring now to FIG. 70, in one embodiment, a tractor rear end assembly6600 includes a drivetrain unit 6605 (for example, a differential unit)with the IVT 4000 coupled thereto. The lubricant sump body 6302 isfixedly attached to the drivetrain unit 6605 (for example, boltedthereto) thereby fixedly attaching the IVT 4000 to the drivetrain unit6605. A power transfer shaft (not shown) of the drivetrain unit 6605 isengaged with the output shaft 2300 for allowing rotational power to betransferred from the IVT 4000 to the drivetrain unit 6605.

Turning now to FIGS. 71-73 and again to FIG. 52, in one embodiment, aninfinitely variable transmission (IVT) 6700 includes a shift-stop-springassembly 6701 and a shift-stop dowel assembly 6702. The shift-stop dowelassembly 6702 can be coupled to the piloting stub 6035 (see FIG. 52) onone end of the shift rod 6000. In one embodiment, the shift-stop dowelassembly 6702 can include a spring 6703 arranged on the inner bore ofthe input shaft 4202 that pilots on the piloting stub 6035. The spring6703 surrounds and retains a shift-stop dowel 6704. An adjustment screw6705 can be coupled to the inner bore of the input shaft 4202. In oneembodiment, the shift-stop-spring assembly 6701 can be coupled to theend of the shift rod on a distal end from the piloting stub 6035 end. Insome embodiments, the shift-stop-spring assembly 6701 can include ashift stop cylinder 6708 coupled to a shift spring 6706. An adjustmentscrew 6710 can thread in the input shaft 4202 and couple to the shiftstop cylinder 6708. The shift spring 6706 can be coupled to one end ofthe shift rod 6000 and pilot on the inner bore of the shift stopcylinder 6708. In some embodiments, the shift stop cylinder 6708 is agenerally hollow cylinder with a closed end having a lubricant drainagehole 6709 and at least one lubricant bleed slot 6707. The lubricantdrainage hole 6709, in cooperation with a flat 6711 formed onto the sideof the adjustment screw 6710, prevents the build-up of lubricantpressure along the inner bore of the input shaft 4202.

During operation of the IVT 6700, the shift rod 6000 translates axiallyto actuate a change in transmission ratio. The range of transmissionratio corresponds at least in part to the axial distance traveled by theshift rod 6000. In some embodiments, the axial travel of the shift rod6000 is limited on one end by the shift-stop-spring assembly 6701, andis limited on another end by the shift-stop-dowel assembly 6702. Duringoperation of the IVT 6700, reaction of the gyroscopic overturning momentthat can be generated in the IVT 6700 is achieved by limiting the axialtravel of the shift rod 6000 with, for example, washers 6750, or withthe shift stop dowel assembly 6702 and the shift-stop-spring assembly6701. Collectively, these means of limiting axial travel of the shiftrod 6000 are called shift stops. The gyroscopic forces imposed onvarious rotating components depend on the axial position of the shiftstops. Shift stops can prevent excess axial travel of theshift-cam-and-sun assembly 1300 due to the gyroscopic forces that tendto tilt the planet-and-shift-lever assemblies 2100 during operation.Without shift stops such as washers 6750, the gyroscopic forces arereacted through the coupling device 1002. In other embodiments, thewashers 6750 can be replaced by springs, such as disc springs or wavesprings to provide some restoring force to the shift rod. The shift stopsprings 6703 and 6706 can provide a restoring force to the shift rod6000. The axial position of the adjustment screws 6705 and 6710 alongthe input shaft 4202 can be adjusted to set the desired maximum axialtravel of the shift rod 6000, and therefore set the desired transmissionratio range.

Still referring to FIG. 71, during loaded operation of the IVT 6700, theplanet-and-shift-lever assemblies 2100 deflect and orient the respectiveplanet longitudinal axis L4 (see FIG. 3) in a direction thatsubsequently creates internal forces that effectively cause the tiltangle of the planet-and-shift-lever assemblies 2100 to change, andthereby change the transmission ratio. This phenomenon is referred hereas “skew” and is a function of, among other things, the backlash (orplay) at the interface between the planet-and-shift-lever assemblies2100 and the stator assembly 1700. Further explanation of skew can befound in U.S. Patent Application 60/948,152. During operation, a skewbacklash generates a small change in transmission ratio known as a ratiobacklash. During certain operating conditions, the skew backlash amongthe planet-and-shift-lever assemblies 2100 is centered and symmetricabout the transmission axis L1 and the effective ratio backlash issubstantially centered about the powered zero state. During conditionswhen the powered zero state is within the ratio backlash, the IVT 6700can maintain the powered zero state by automatically changing thetransmission ratio. It is preferred to provide enough skew backlash toallow the operation described. There is a small but definite range forthe skew backlash which will provide optimum control feel andperformance. In some instances, skew backlash is in the range of 0.002to 0.004 inches measured between the interfaces of theplanet-and-shift-lever assemblies 2100 and the stator assembly 1700. Insome embodiments, a brake (not shown) can be coupled to the output ofIVT 6700 and engaged, without damaging the IVT, to ensure a zero outputspeed. In one embodiment, a switch, positioned on a control linkage forexample, engages the brake through an electromotive actuator. In otherembodiments, a clutch can be coupled to the input shaft 4202 and to theprime mover of the vehicle. In one embodiment, the clutch can be, forexample, an automotive grade air conditioner compressor clutch with apulley interface for a mid-1990's Honda Accord, or other appropriatelysized clutching mechanism. A method to maintain the powered zero statecan include actuating the clutch to disengage the input shaft 4202 fromthe prime mover when the transmission ratio is near the powered zerostate. This method can reduce sensitivity to an error in the set pointfor the powered zero state.

Various embodiments of subassemblies are disclosed herein and eachincludes respective components thereof. It is disclosed herein that suchsubassemblies are not limited to the specific constituent componentsshown herein. For example, each one of such subassemblies can includefew, greater and/or different constituent components disclosed herein.Furthermore, the functionality provided by a subassembly disclosedherein can be provided by a collection of components that are notcharacterized or deemed to be a subassembly. Furthermore, the bearingsand bushings can be used interchangeably in some or all of theirimplementations. Still further, unless otherwise specified, theinventive embodiments are not limited to bearings being of a particulartype.

The embodiments described herein are examples provided to meet thedescriptive requirements of the law and to provide examples. Theseexamples are only embodiments that can be employed by any party and theyare not intended to be limiting in any manner. Therefore, the inventionis defined by the claims that follow and not by any of the examples orterms used herein.

1. An infinitely variable transmission comprising: a rotatable inputshaft arranged along a longitudinal axis of the transmission, the inputshaft adapted to supply a lubricant to the interior of the transmission;a stator assembly coupled to, and coaxial with, the input shaft; aplurality of planets operably coupled to the stator assembly, whereinthe planets are arranged angularly about the longitudinal axis of thetransmission; a traction ring operably coupled to the planets, whereinthe traction ring is substantially fixed from rotating with the inputshaft; and a housing operably coupled to the traction ring, wherein thehousing is substantially fixed from rotating with the input shaft. 2.The infinitely variable transmission of claim 1, wherein the input shaftand the stator assembly are rigidly coupled.
 3. The infinitely variabletransmission of claim 1, wherein the traction ring further comprises: asubstantially annular ring having a front face and a rear face; aplurality of bi-directional ramps located on the front face, wherein thecross-section of the ramps is curved; and a contact surface located onthe rear face.
 4. The infinitely variable transmission of claim 3,further comprising a lubricant manifold configured to supply a lubricantto the input shaft.
 5. The infinitely variable transmission of claim 4,further comprising a load cam ring coaxial with the plurality ofplanets, the load cam ring comprising: a substantially annular ringhaving a front face and a rear face; a plurality of bi-directional rampslocated on the front face of the load cam ring, wherein thecross-section of said ramps is curved; and a plurality of engagementfeatures located on the rear face of the load cam ring.
 6. Theinfinitely variable transmission of claim 5, further comprising aplurality of load cam rollers coupled to the load cam ring.
 7. Theinfinitely variable transmission of claim 4, further comprising a shiftrod coupled to the input shaft.
 8. The infinitely variable transmissionof claim 7, wherein the shift rod is arranged in a central bore of theinput shaft.
 9. The infinitely variable transmission of claim 7, whereinthe shift rod is adapted to supply a lubricant to the interior of thetransmission.
 10. A method for lubricating internal components of atransmission having a plurality of planets operably coupled to a statorassembly, and a traction ring operably coupled to the planets, themethod comprising: providing a lubricant manifold configured tocooperate with a lubricant source; coupling a main axle of thetransmission to the lubricant manifold, wherein the main axle is adaptedto receive a rotational power; providing a shift rod arranged in acentral bore of the main axle, the shift rod having a central bore;supplying a lubricant via the lubricant manifold to the main axle;delivering the lubricant via a main axle lubricant passage to the shiftrod; delivering the lubricant through the central bore of the shift rodto a shift rod lubricant passage; providing a housing operably coupledto the traction ring, wherein the housing is substantially fixed fromrotating with the main axle; and adapting the traction ring to besubstantially fixed from rotating with the main axle.
 11. The method ofclaim 10, further comprising supplying a pressurized lubricant via thelubricant source.
 12. The method of claim 11, further comprisingdelivering the lubricant through a lubricant delivery passage of themain axle to the interior of the transmission.
 13. An infinitelyvariable transmission comprising: a lubricant manifold configured tocooperate with a lubricant source; a rotatable input shaft arrangedalong a longitudinal axis of the transmission, the input shaft coupledto the lubricant manifold, the input shaft adapted to supply a lubricantto the interior of the transmission; a stator assembly coupled to, andcoaxial with, the input shaft; a plurality of planets operably coupledto the stator assembly, wherein the planets are arranged angularly aboutthe longitudinal axis of the transmission; a traction ring operablycoupled to the planets, wherein the traction ring is substantially fixedfrom rotating with the input shaft; and a housing operably coupled tothe traction ring, wherein the housing is substantially fixed fromrotating with the input shaft.
 14. The transmission of claim 13, whereinthe lubricant source is pressurized.
 15. The transmission of claim 14,further comprising a load cam ring coaxial with the plurality ofplanets, the load cam ring comprising: a substantially annular ringhaving a front face and a rear face; a plurality of bi-directional rampslocated on the front face of the load cam ring, wherein thecross-section of said ramps is curved; and a plurality of engagementfeatures located on the rear face of the load cam ring.
 16. Thetransmission of claim 15, wherein the traction ring further comprises: asubstantially annular ring having a front face and a rear face; aplurality of bi-directional ramps located on the front face, wherein thecross-section of the ramps is curved; and a contact surface located onthe rear face.